diff --git a/fnhid/AdHoc/1813.cpp b/fnhid/AdHoc/1813.cpp
new file mode 100644
index 0000000..bea3353
--- /dev/null
+++ b/fnhid/AdHoc/1813.cpp
@@ -0,0 +1,28 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+int main()
+{
+    int n, t;
+    cin >> n;
+    vector <int> a(51, 0);
+    for(int i=0;i<n;i++){
+        cin >> t;
+        a[t]++;
+    }
+     
+    for(int i=50;i>0;i--){
+        if(a[i]==i) {
+            cout << i;
+            return 0;
+        }
+    }    
+    
+    if(a[0]==0) cout << 0;
+    else cout << -1;
+    
+    return 0;
+        
+
+}
\ No newline at end of file
diff --git a/fnhid/PriorityQueue/1374.cpp b/fnhid/PriorityQueue/1374.cpp
new file mode 100644
index 0000000..4eab974
--- /dev/null
+++ b/fnhid/PriorityQueue/1374.cpp
@@ -0,0 +1,49 @@
+#include <iostream>
+#include <queue>
+#include <vector>
+#include <algorithm>
+
+struct Lecture
+{
+    long long start, end;
+};
+
+int max(int a, int b)
+{
+    return a > b ? a : b;
+}
+
+using namespace std;
+
+int main()
+{
+    int n, id, start, end, answer=0;
+    priority_queue<long long, vector<long long>, greater<long long>> pq;
+
+
+    cin >> n;
+    vector<Lecture> v(n);
+    for (int i=0;i<n;i++)
+    {
+        cin >> id >> start >> end;
+        v.push_back({start, end});
+    }
+
+    sort(v.begin(), v.end(), [](const Lecture& a, const Lecture& b)
+    {
+        return a.start < b.start;
+    });
+
+    for (Lecture& l : v)
+    {
+
+        while (!pq.empty() && pq.top() <= l.start)
+            pq.pop();
+        pq.push(l.end);
+        answer = max(answer, (int)pq.size());
+    }
+
+
+    cout << answer;
+
+}
\ No newline at end of file
diff --git a/fnhid/README.md b/fnhid/README.md
index eaad859..36516fb 100644
--- a/fnhid/README.md
+++ b/fnhid/README.md
@@ -1,6 +1,12 @@
 ## ✏️ 기록
 
-|  차시  |     날짜     |    문제유형    |                     링크                      |                         풀이                          |
- |:----:|:----------:|:----------:|:-------------------------------------------:|:---------------------------------------------------:|
-| 16차시 | 2025.06.25 | 다이나믹 프로그래밍 | [균형](https://www.acmicpc.net/problem/22968) | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/64 |
+|  차시  |     날짜     |    문제유형    |                              링크                              |                         풀이                          |
+ |:----:|:----------:|:----------:|:------------------------------------------------------------:|:---------------------------------------------------:|
+| 16차시 | 2025.06.25 | 다이나믹 프로그래밍 |         [균형](https://www.acmicpc.net/problem/22968)          | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/64 |
+| 17차시 | 2025.06.27 |  KMP 알고리즘  |          [찾기](https://www.acmicpc.net/problem/1786)          | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/67 |
+| 18차시 | 2025.07.05 |    그래프     | [여러분의 다리가 되어 드리겠습니다!](https://www.acmicpc.net/problem/17352) | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/73 |
+| 19차시 | 2025.07.06 |     큐      |          [뱀](https://www.acmicpc.net/problem/3190)           | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/74 |
+| 20차시 | 2025.07.12 |   우선순위 큐   |         [강의실](https://www.acmicpc.net/problem/1374)          | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/80 |
+| 21차시 | 2025.07.14 |   투 포인터    |          [좋다](https://www.acmicpc.net/problem/1253)          | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/83 |
+| 22차시 | 2025.07.18 |    애드 혹    |        [논리학 교수](https://www.acmicpc.net/problem/1813)        | https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/86 |
  
\ No newline at end of file
diff --git a/fnhid/TwoPointer/1253.cpp b/fnhid/TwoPointer/1253.cpp
new file mode 100644
index 0000000..375b0a1
--- /dev/null
+++ b/fnhid/TwoPointer/1253.cpp
@@ -0,0 +1,44 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+
+int main() {
+  cin.sync_with_stdio(false);
+  cin.tie(NULL);
+  int n, cnt=0, target, l, r, sum;
+
+  cin >> n;
+
+  vector<int> v(n,0);
+
+  for (int i = 0; i < n; i++) {
+    cin >> v[i];
+  }
+  sort(v.begin(), v.end());
+
+
+  for (int i = 0; i < n; i++) {
+    l=0;r=n-1;
+    target = v[i];
+    while (l < r){
+      if (l==i) {l++;continue;}
+      if (r==i) {r--;continue;}
+      sum=v[r]+v[l];
+      if (sum==target) {
+        cnt++;
+        break;
+      } else if (sum < target) {
+        l++;
+      } else {
+        r--;
+      }
+
+    }
+  }
+
+  cout << cnt << endl;
+  return 0;
+}