diff --git a/froglike6/README.md b/froglike6/README.md
index 481fad0..581e485 100644
--- a/froglike6/README.md
+++ b/froglike6/README.md
@@ -24,4 +24,5 @@
  | 20차시 | 2025.07.09 | 조합론 | [암호 만들기](https://www.acmicpc.net/problem/1759)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/77|
  | 21차시 | 2025.07.14 | 기하학 | [Cows](https://www.acmicpc.net/problem/6850)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/82|
  | 22차시 | 2025.07.22 | 그래프 | [밤(Time For The Moon Night)](https://www.acmicpc.net/problem/34064)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/88|
+ | 23차시 | 2025.07.22 | 정수 | [Fibonacci](https://www.acmicpc.net/problem/7677)|https://github.com/AlgoLeadMe/AlgoLeadMe-13/pull/89|
  ---
diff --git a/froglike6/number_theory/7677.java b/froglike6/number_theory/7677.java
new file mode 100644
index 0000000..3ab6c40
--- /dev/null
+++ b/froglike6/number_theory/7677.java
@@ -0,0 +1,53 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static final int MOD = 10000;
+
+    public static int fibo(long n) {
+        long m00 = 1, m01 = 1, m10 = 1, m11 = 0;
+        long v0 = 1, v1 = 0;
+
+        while (n > 0) {
+            if ((n & 1) == 1) {
+                long t0 = (m00 * v0 + m01 * v1) % MOD;
+                long t1 = (m10 * v0 + m11 * v1) % MOD;
+                v0 = t0;
+                v1 = t1;
+            }
+            long a = (m00 * m00 + m01 * m10) % MOD;
+            long b = (m00 * m01 + m01 * m11) % MOD;
+            long c = (m10 * m00 + m11 * m10) % MOD;
+            long d = (m10 * m01 + m11 * m11) % MOD;
+            m00 = a; m01 = b;
+            m10 = c; m11 = d;
+
+            n >>= 1;
+        }
+        return (int) v1;
+    }
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        List<Long> inputs = new ArrayList<>();
+        String line;
+
+        while ((line = br.readLine()) != null) {
+            line = line.trim();
+            if (!line.isEmpty()) {
+                inputs.add(Long.parseLong(line));
+            }
+        }
+        if (!inputs.isEmpty()) {
+            inputs.remove(inputs.size() - 1);
+        }
+
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        for (long n : inputs) {
+            bw.write(fibo(n) + "\n");
+        }
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+}
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