diff --git a/Seol-Munhyeok/.cph/.ATM.py_0961ba91b3ef35ddeba6bb2caf378d6c.prob b/Seol-Munhyeok/.cph/.ATM.py_0961ba91b3ef35ddeba6bb2caf378d6c.prob
new file mode 100644
index 0000000..a55e59e
--- /dev/null
+++ b/Seol-Munhyeok/.cph/.ATM.py_0961ba91b3ef35ddeba6bb2caf378d6c.prob
@@ -0,0 +1 @@
+{"name":"Local: ATM","url":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\ATM.py","tests":[{"id":1756627725177,"input":"5\n3 1 4 3 2","output":"32"}],"interactive":false,"memoryLimit":1024,"timeLimit":3000,"srcPath":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\ATM.py","group":"local","local":true}
\ No newline at end of file
diff --git "a/Seol-Munhyeok/.cph/.\352\260\234\353\230\245\353\262\214\353\240\210.py_478b34ffa2be96fa5b5b2fbb1687d64c.prob" "b/Seol-Munhyeok/.cph/.\352\260\234\353\230\245\353\262\214\353\240\210.py_478b34ffa2be96fa5b5b2fbb1687d64c.prob"
new file mode 100644
index 0000000..bdeb570
--- /dev/null
+++ "b/Seol-Munhyeok/.cph/.\352\260\234\353\230\245\353\262\214\353\240\210.py_478b34ffa2be96fa5b5b2fbb1687d64c.prob"
@@ -0,0 +1 @@
+{"name":"Local: 개똥벌레","url":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\개똥벌레.py","tests":[{"id":1756972182171,"input":"14 5\n1\n3\n4\n2\n2\n4\n3\n4\n3\n3\n3\n2\n3\n3","output":"7 2"},{"id":1756972205164,"input":"6 7\n1\n5\n3\n3\n5\n1","output":"2 3"}],"interactive":false,"memoryLimit":1024,"timeLimit":3000,"srcPath":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\개똥벌레.py","group":"local","local":true}
\ No newline at end of file
diff --git "a/Seol-Munhyeok/.cph/.\352\260\234\353\230\245\353\262\214\353\240\2102.py_f7b1bfedf84554024f689b69b61e08ce.prob" "b/Seol-Munhyeok/.cph/.\352\260\234\353\230\245\353\262\214\353\240\2102.py_f7b1bfedf84554024f689b69b61e08ce.prob"
new file mode 100644
index 0000000..465ebc2
--- /dev/null
+++ "b/Seol-Munhyeok/.cph/.\352\260\234\353\230\245\353\262\214\353\240\2102.py_f7b1bfedf84554024f689b69b61e08ce.prob"
@@ -0,0 +1 @@
+{"name":"Local: 개똥벌레2","url":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\개똥벌레2.py","tests":[{"id":1756973855147,"input":"14 5\n1\n3\n4\n2\n2\n4\n3\n4\n3\n3\n3\n2\n3\n3","output":"7 2"},{"id":1756974701757,"input":"6 7\n1\n5\n3\n3\n5\n1","output":"2 3"}],"interactive":false,"memoryLimit":1024,"timeLimit":3000,"srcPath":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\개똥벌레2.py","group":"local","local":true}
\ No newline at end of file
diff --git "a/Seol-Munhyeok/.cph/.\354\240\234\352\263\261\354\210\230\354\260\276\352\270\260.py_ea7559ebea594486c87e81b9ee32f04b.prob" "b/Seol-Munhyeok/.cph/.\354\240\234\352\263\261\354\210\230\354\260\276\352\270\260.py_ea7559ebea594486c87e81b9ee32f04b.prob"
new file mode 100644
index 0000000..48038c1
--- /dev/null
+++ "b/Seol-Munhyeok/.cph/.\354\240\234\352\263\261\354\210\230\354\260\276\352\270\260.py_ea7559ebea594486c87e81b9ee32f04b.prob"
@@ -0,0 +1 @@
+{"name":"Local: 제곱수찾기","url":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\제곱수찾기.py","tests":[{"id":1755608679338,"input":"2 3\n123\n456","output":"64"},{"id":1755610569758,"input":"9 9\n257240281\n197510846\n014345401\n035562575\n974935632\n865865933\n684684987\n768934659\n287493867","output":"95481"},{"id":1755613365657,"input":"1 1\n1","output":""},{"id":1755613442978,"input":"1 2\n12","output":""}],"interactive":false,"memoryLimit":1024,"timeLimit":3000,"srcPath":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\제곱수찾기.py","group":"local","local":true}
\ No newline at end of file
diff --git "a/Seol-Munhyeok/.cph/.\354\260\250\353\237\211\353\260\260\354\271\230.py_1ee6dc7200a143d3ff95e315a3e7cb91.prob" "b/Seol-Munhyeok/.cph/.\354\260\250\353\237\211\353\260\260\354\271\230.py_1ee6dc7200a143d3ff95e315a3e7cb91.prob"
new file mode 100644
index 0000000..bdbc1c9
--- /dev/null
+++ "b/Seol-Munhyeok/.cph/.\354\260\250\353\237\211\353\260\260\354\271\230.py_1ee6dc7200a143d3ff95e315a3e7cb91.prob"
@@ -0,0 +1 @@
+{"name":"Local: 차량배치","url":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\차량배치.py","tests":[{"id":1756981134725,"input":"3 3\n1 2\n1 3\n2 3","output":"5"},{"id":1756981248426,"input":"3 2\n1 2\n2 3","output":"7"},{"id":1756981481893,"input":"6 5\n1 2\n1 3\n2 4\n2 5\n3 6","output":"23"},{"id":1756981635073,"input":"1 0\n","output":"1"}],"interactive":false,"memoryLimit":1024,"timeLimit":3000,"srcPath":"d:\\AlgoLeadME-15\\AlgoLeadMe-15\\Seol-Munhyeok\\차량배치.py","group":"local","local":true}
\ No newline at end of file
diff --git "a/Seol-Munhyeok/30\353\262\210" "b/Seol-Munhyeok/30\353\262\210"
new file mode 100644
index 0000000..4fb7649
--- /dev/null
+++ "b/Seol-Munhyeok/30\353\262\210"
@@ -0,0 +1,7 @@
+t = int(input())
+for _ in range(t):
+    a, b = map(int, input().split())
+    while a != b:
+        if a > b: a //= 2
+        else: b //= 2
+    print(10 * a)
\ No newline at end of file
diff --git a/Seol-Munhyeok/ATM.py b/Seol-Munhyeok/ATM.py
new file mode 100644
index 0000000..1e06690
--- /dev/null
+++ b/Seol-Munhyeok/ATM.py
@@ -0,0 +1,10 @@
+n = int(input())
+lst = list(map(int, input().split()))
+
+lst.sort()
+p_sum = [0] * (n + 1)
+
+for i in range(n):
+    p_sum[i + 1] = p_sum[i] + lst[i]
+
+print(sum(p_sum))
diff --git a/Seol-Munhyeok/README.md b/Seol-Munhyeok/README.md
index cc2a4c4..adea734 100644
--- a/Seol-Munhyeok/README.md
+++ b/Seol-Munhyeok/README.md
@@ -15,4 +15,8 @@
 | 19차시 | 2025.08.10 | 구현, BFS | [거리두기 확인하기](https://school.programmers.co.kr/learn/courses/30/lessons/81302) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/67 |
 | 20차시 | 2025.08.14 | DP | [코딩 테스트 공부](https://school.programmers.co.kr/learn/courses/30/lessons/118668) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/73 |
 AlgoLeadMe/AlgoLeadMe-15/pull/67 |
-| 21차시 | 2025.08.18 | 시뮬레이션, 그리디 | [양궁 대회](https://school.programmers.co.kr/learn/courses/30/lessons/92342) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/75 |
\ No newline at end of file
+| 21차시 | 2025.08.18 | 시뮬레이션, 그리디 | [양궁 대회](https://school.programmers.co.kr/learn/courses/30/lessons/92342) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/75 |
+| 22차시 | 2025.08.23 | 그리디, 투 포인터 | [두 큐 합 같게 만들기](https://school.programmers.co.kr/learn/courses/30/lessons/118667) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/79 |
+| 23차시 | 2025.09.03 | 수학, 구현 | [책 페이지](https://www.acmicpc.net/problem/1019) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/84 |
+| 24차시 | 2025.09.03 | 구현 | [수식 최대화](https://school.programmers.co.kr/learn/courses/30/lessons/67257) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/85 |
+| 25차시 | 2025.09.06 | 문자열, 구현 | [방금그곡](https://school.programmers.co.kr/learn/courses/30/lessons/17683) | https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/86 |
diff --git a/Seol-Munhyeok/tempCodeRunnerFile.py b/Seol-Munhyeok/tempCodeRunnerFile.py
index aad8b78..d00e753 100644
--- a/Seol-Munhyeok/tempCodeRunnerFile.py
+++ b/Seol-Munhyeok/tempCodeRunnerFile.py
@@ -1,4 +1 @@
-# 7 6 2 3 15 6 9 8
-# 3 1 1 8 14 7 10 1
-# 6 1 13 6 4 3 11 4
-# 16 1 8 7 5 2 12 2
\ No newline at end of file
+down
\ No newline at end of file
diff --git "a/Seol-Munhyeok/\352\260\234\353\230\245\353\262\214\353\240\210.py" "b/Seol-Munhyeok/\352\260\234\353\230\245\353\262\214\353\240\210.py"
new file mode 100644
index 0000000..a9cdfcf
--- /dev/null
+++ "b/Seol-Munhyeok/\352\260\234\353\230\245\353\262\214\353\240\210.py"
@@ -0,0 +1,28 @@
+from bisect import bisect_left
+
+# 입력 처리
+N, H = map(int, input().split())
+down, up = [], []
+for i in range(N):
+    h = int(input())
+    if i % 2 == 0:
+        down.append(h)
+    else:
+        up.append(h)
+
+down.sort()
+up.sort()
+
+best = int(1e9)  # 파괴해야 하는 장애물의 최솟값
+way = 1  # 구간의 수
+for h in range(1, H + 1):
+    cnt_down = N // 2 - bisect_left(down, h)
+    cnt_up = N // 2 - bisect_left(up, H - h + 1)
+    cnt = cnt_down + cnt_up
+    if best > cnt:
+        best = cnt
+        way = 1
+    elif best == cnt:
+        way += 1
+        
+print(best, way)
diff --git "a/Seol-Munhyeok/\352\260\234\353\230\245\353\262\214\353\240\2102.py" "b/Seol-Munhyeok/\352\260\234\353\230\245\353\262\214\353\240\2102.py"
new file mode 100644
index 0000000..f9db7c7
--- /dev/null
+++ "b/Seol-Munhyeok/\352\260\234\353\230\245\353\262\214\353\240\2102.py"
@@ -0,0 +1,28 @@
+import sys
+input = sys.stdin.readline
+
+N, H = map(int, input().split())
+
+# line[i] = 높이 i에서 시작되는 충돌 변화량
+line = [0] * H
+
+for t in range(N):
+    h = int(input())
+    if t % 2 == 0:  # 석순(아래에서 위로 올라옴)
+        line[0] += 1
+        line[h] -= 1
+    else:  # 종유석(위에서 아래로 내려옴)
+        line[H - h] += 1
+
+# prefix[y] = 높이 y에서 총 충돌 개수
+prefix = [0] * (H + 1)
+for i in range(H):
+    prefix[i + 1] = prefix[i] + line[i]
+
+prefix = prefix[1:]
+
+print(line)
+print(prefix)
+best = min(prefix)
+way = prefix.count(best)
+print(best, way)
diff --git "a/Seol-Munhyeok/\353\221\220\355\201\220\355\225\251\352\260\231\352\262\214\353\247\214\353\223\244\352\270\2601.py" "b/Seol-Munhyeok/\353\221\220\355\201\220\355\225\251\352\260\231\352\262\214\353\247\214\353\223\244\352\270\2601.py"
new file mode 100644
index 0000000..160d420
--- /dev/null
+++ "b/Seol-Munhyeok/\353\221\220\355\201\220\355\225\251\352\260\231\352\262\214\353\247\214\353\223\244\352\270\2601.py"
@@ -0,0 +1,26 @@
+from collections import deque
+
+def solution(queue1, queue2):
+    q1, q2 = deque(queue1), deque(queue2)
+    sum1, sum2 = sum(q1), sum(q2)
+
+    if (sum1 + sum2) % 2 == 1:
+        return -1
+    
+    n = len(q1)
+    for i in range(4*n+1):
+        if sum1 > sum2:
+            value = q1.popleft()
+            q2.append(value)
+            sum1 -= value
+            sum2 += value
+        elif sum1 < sum2:
+            value = q2.popleft()
+            q1.append(value)
+            sum2 -= value
+            sum1 += value
+        else:
+            return i
+        
+    return -1
+    
\ No newline at end of file
diff --git "a/Seol-Munhyeok/\353\221\220\355\201\220\355\225\251\352\260\231\352\262\214\353\247\214\353\223\244\352\270\2602.py" "b/Seol-Munhyeok/\353\221\220\355\201\220\355\225\251\352\260\231\352\262\214\353\247\214\353\223\244\352\270\2602.py"
new file mode 100644
index 0000000..07c1ffa
--- /dev/null
+++ "b/Seol-Munhyeok/\353\221\220\355\201\220\355\225\251\352\260\231\352\262\214\353\247\214\353\223\244\352\270\2602.py"
@@ -0,0 +1,30 @@
+# 투 포인터 풀이
+# https://blog.encrypted.gg/1076 를 참고함
+
+def solution(queue1, queue2):
+    n = len(queue1)
+    a = queue1 + queue2
+    target = sum(a)
+    if target % 2 != 0:
+        return -1
+    target //= 2 # 합이 target이 되는 구간을 찾아야 함
+    
+    ans = int(1e9) # 일단 매우 큰 값을 넣어놓고 시작
+    en = 0
+    tot = a[0] # 현재 보는 구간의 합 = a[st]+...+a[en], 범위가 양 끝을 포함(inclusive)한다는 점과 en < st일 땐 a[st]+...+a[2*n-1]+a[0]+...+a[en]을 나타냄에 주의
+    for st in range(2*n):
+        while tot < target:
+            en = (en + 1) % (2*n)
+            tot += a[en]
+        
+        # while문을 탈출하면 a[st]+...+a[en] 구간의 합이 target 이상임을 의미
+        if tot == target: # 구간의 합이 정확히 target과 일치할 경우
+            moves = 0 # 작업 횟수
+            if en < n-1: moves = 3*n + 1 + st + en # 3n+1번의 연산을 통해 큐1에 첫 번째 원소만 남길 수 있고, 이후 st+en 번의 추가적인 연산을 거쳐 a[st] .. a[en]을 큐1에 둘 수 있음
+            else: moves = st + (en - n + 1)
+            ans = min(ans, moves)
+        
+        tot -= a[st]
+    
+    if ans == int(1e9): ans = -1
+    return ans
\ No newline at end of file
diff --git "a/Seol-Munhyeok/\353\247\244\354\232\260\354\226\264\353\240\244\354\232\264\353\254\270\354\240\234.py" "b/Seol-Munhyeok/\353\247\244\354\232\260\354\226\264\353\240\244\354\232\264\353\254\270\354\240\234.py"
new file mode 100644
index 0000000..a3fde68
--- /dev/null
+++ "b/Seol-Munhyeok/\353\247\244\354\232\260\354\226\264\353\240\244\354\232\264\353\254\270\354\240\234.py"
@@ -0,0 +1,12 @@
+n, m = map(int, input().split())
+
+def solution(n, m):
+    if n > m:
+        return 0 
+    tmp = 1
+    for i in range(2, n+1):
+        tmp = (tmp * i) % m
+    return tmp
+
+print(solution(n, m))
+
diff --git "a/Seol-Munhyeok/\353\260\251\352\270\210\352\267\270\352\263\241.py" "b/Seol-Munhyeok/\353\260\251\352\270\210\352\267\270\352\263\241.py"
new file mode 100644
index 0000000..04ca03e
--- /dev/null
+++ "b/Seol-Munhyeok/\353\260\251\352\270\210\352\267\270\352\263\241.py"
@@ -0,0 +1,32 @@
+def time_to_sec(time):
+    h, m = time.split(":")
+    return 60 * int(h) + int(m)
+
+def convert(score):
+    lst = [("B#", "b"), ("C#", "c"), ("D#", "d"), ("E#", "e"), ("F#", "f"), ("G#", "g"), ("A#", "a")]
+    for a, b in lst:
+        score = score.replace(a, b)        
+    return score
+
+def convert_2(score, length):    
+    size = len(score)
+    if size == length:
+        return score
+    if size > length:
+        return score[:length]
+    if size < length:
+        return score * (length // size) + score[:length % size]
+
+
+def solution(m, musicinfos):
+    answer = '(None)'
+    max_size = -1
+    for info in musicinfos:
+        start, end, title, score = info.split(",")
+        length = time_to_sec(end) - time_to_sec(start)
+        m, score = convert(m), convert(score)
+        if m in convert_2(score, length) and length > max_size:
+            answer = title
+            max_size = length
+            
+    return answer
\ No newline at end of file
diff --git "a/Seol-Munhyeok/\354\210\230\354\213\235\354\265\234\353\214\200\355\231\224.py" "b/Seol-Munhyeok/\354\210\230\354\213\235\354\265\234\353\214\200\355\231\224.py"
new file mode 100644
index 0000000..bd1b103
--- /dev/null
+++ "b/Seol-Munhyeok/\354\210\230\354\213\235\354\265\234\353\214\200\355\231\224.py"
@@ -0,0 +1,43 @@
+from itertools import permutations
+
+def solution(expression):
+    # 토큰 분리
+    token = []
+    operators = set()
+    num = ''
+    for e in expression:
+        if e.isdigit():
+            num += e
+        else:
+            token.append(int(num))
+            token.append(e)
+            operators.add(e)
+            num = ''
+    token.append(int(num))
+
+    max_val = -1
+    # 모든 우선 순위 고려
+    for ops in permutations(operators):
+        temp = token[:]
+        # 연산자 우선 순위대로 처리
+        for op in ops:
+            stack = []
+            i = 0
+            while i < len(temp):
+                if temp[i] == op:
+                    val_1 = stack.pop()
+                    val_2 = temp[i + 1]
+                    if op == '+':
+                        stack.append(val_1 + val_2)
+                    elif op == '-':
+                        stack.append(val_1 - val_2)
+                    elif op == '*':
+                        stack.append(val_1 * val_2)
+                    i += 2
+                else:
+                    stack.append(temp[i])
+                    i += 1
+            temp = stack
+        max_val = max(max_val, abs(temp[0]))
+                           
+    return max_val
\ No newline at end of file
diff --git "a/Seol-Munhyeok/\354\240\234\352\263\261\354\210\230\354\260\276\352\270\260.py" "b/Seol-Munhyeok/\354\240\234\352\263\261\354\210\230\354\260\276\352\270\260.py"
new file mode 100644
index 0000000..fefb98c
--- /dev/null
+++ "b/Seol-Munhyeok/\354\240\234\352\263\261\354\210\230\354\260\276\352\270\260.py"
@@ -0,0 +1,33 @@
+import math 
+
+answer = -1
+
+def is_square(n):
+    return math.isqrt(n) ** 2 == n
+
+def brute():
+    global answer
+    if n == 1 and m == 1:
+        return A[0][0] if is_square(int(A[0][0])) else -1
+    
+    for r0 in range(n):
+        for c0 in range(m):
+            for dr in range(-(n-1), n):
+                for dc in range(-(m-1), m):
+                    if dr == 0 and dc == 0:
+                        continue
+                    r, c = r0, c0
+                    num = ""
+                    while 0 <= r < n and 0 <= c < m:
+                        num += A[r][c]
+                        val = int(num)
+                        if is_square(val):
+                            answer = max(answer, val)
+                        r += dr
+                        c += dc
+    return answer
+
+n, m = map(int, input().split())
+A = [list(input()) for _ in range(n)]
+
+print(brute())
\ No newline at end of file
diff --git "a/Seol-Munhyeok/\354\260\250\353\237\211\353\260\260\354\271\230.py" "b/Seol-Munhyeok/\354\260\250\353\237\211\353\260\260\354\271\230.py"
new file mode 100644
index 0000000..44d7df0
--- /dev/null
+++ "b/Seol-Munhyeok/\354\260\250\353\237\211\353\260\260\354\271\230.py"
@@ -0,0 +1,28 @@
+from collections import defaultdict, deque
+import sys
+
+input = sys.stdin.readline
+N, M = map(int, input().split())
+graph = defaultdict(list)
+for _ in range(M):
+    a, b = map(int, input().split())
+    graph[a].append(b)
+    graph[b].append(a)
+
+visited = [False] * (N+1)
+queue = deque()
+queue.append(1)
+visited[1] = True
+answer = 1
+
+while queue:
+    size = len(queue)
+    answer *= (size + 1)
+    for _ in range(size):
+        cur = queue.popleft()
+        for neighbor in graph[cur]:
+            if not visited[neighbor]:
+                queue.append(neighbor)
+                visited[neighbor] = True
+
+print((answer - 1) % 1_000_000_007)
\ No newline at end of file
diff --git "a/Seol-Munhyeok/\354\261\205 \355\216\230\354\235\264\354\247\200.py" "b/Seol-Munhyeok/\354\261\205 \355\216\230\354\235\264\354\247\200.py"
new file mode 100644
index 0000000..b8a0ba1
--- /dev/null
+++ "b/Seol-Munhyeok/\354\261\205 \355\216\230\354\235\264\354\247\200.py"	
@@ -0,0 +1,48 @@
+answer = [0] * 10  # 0~9 각 숫자의 총 등장 횟수를 담을 배열
+
+start = 1  # 왼쪽 포인터: 아직 세지 않은 최소 숫자
+end = int(input())    # 오른쪽 포인터: 아직 세지 않은 최대 숫자(입력 N)
+ten = 1  # 현재 바라보는 자릿값(일=1, 십=10, 백=100, ...)
+
+# 숫자 n이 지금 바라보는 자릿값(ten=1,10,100,...)에서
+# '접두사'로서 기여하는 고정 등장 횟수를 answer에 더한다.
+# 예를들어 calc(12345, 1)은 answer[5], answer[4], ... answer[1]에 +1
+# +ten을 하는 이유는 현재 자리 아래쪽에는 항상 ten가지(0..ten-1)의 조합이 깔리므로,
+# 그 자리의 같은 숫자 d가 블록 안에서 정확히 ten번 등장하기 때문.
+def calc(n, ten):
+    while n > 0:
+        answer[n % 10] += ten
+        n //= 10
+
+# 바깥 while 한 바퀴 = 자릿값 'ten' 하나를 완전히 처리
+while start <= end:
+    # [1] 왼쪽 모서리 정리: start를 '...0'으로 맞출 때까지 개별 처리
+    while start % 10 != 0 and start <= end:
+        calc(start, ten)
+        start += 1
+    if start > end: break  # 다 끝나면 종료
+
+    # [2] 오른쪽 모서리 정리: end를 '...9'로 맞출 때까지 개별 처리
+    while end % 10 != 9 and start <= end:
+        calc(end, ten)
+        end -= 1
+
+    # 여기까지 오면 [start, end]는 현재 자리에서
+    # 정확히 '...0 ~ ...9'가 반복되는 '완전 주기 구간'이 됨.
+
+    # [3] 가운데 완전 주기 한 번에 더하기
+    # cnt = 현재 자리에서 서로 다른 '접두사' 개수
+    # (접두사 하나마다 0~9 각 숫자가 하위 ten가지와 결합하므로
+    # 각 숫자가 정확히 'ten'번씩 등장)
+    cnt = (end // 10) - (start) // 10 + 1
+    for d in range(0, 10):
+        answer[d] += cnt * ten
+
+    # [4] 한 자리 올림: 현재 자리 처리를 끝냈으니 윗자리로 이동
+    start //= 10
+    end //= 10
+    ten *= 10
+
+# 결과 출력
+for d in range(0, 10):
+    print(answer[d], end=' ')
diff --git "a/Seol-Munhyeok/\355\206\240\353\247\210\355\206\240.py" "b/Seol-Munhyeok/\355\206\240\353\247\210\355\206\240.py"
new file mode 100644
index 0000000..3fcf980
--- /dev/null
+++ "b/Seol-Munhyeok/\355\206\240\353\247\210\355\206\240.py"
@@ -0,0 +1,37 @@
+from collections import deque
+import sys
+
+m, n = map(int, input().split())
+arr = []
+dy, dx = [-1, 0, 1, 0], [0, 1, 0, -1]
+queue = deque()
+
+# 입력 처리, 1인 좌표 저장
+for i in range(n):
+    row = []
+    for j, val in enumerate(map(int, input().split())):
+        row.append(val)
+        if val == 1:
+            queue.append((i, j))
+    arr.append(row)
+
+# BFS
+while queue:
+    y, x = queue.popleft()
+    for i in range(4):
+        ny, nx = y + dy[i], x + dx[i]
+        if 0 <= ny < n and 0 <= nx < m and arr[ny][nx] == 0:
+            arr[ny][nx] = arr[y][x] + 1
+            queue.append((ny, nx))
+
+# 정답 찾기
+answer = -1e9
+for i in range(n):
+    for j in range(m):
+        if arr[i][j] == 0:
+            print(-1)
+            sys.exit()
+        if arr[i][j] > answer:
+            answer = arr[i][j]
+            
+print(answer - 1)