diff --git a/jinu-ahn/BOJ_15961.java b/jinu-ahn/BOJ_15961.java
new file mode 100644
index 0000000..f0c9b3d
--- /dev/null
+++ b/jinu-ahn/BOJ_15961.java
@@ -0,0 +1,57 @@
+import java.io.*;
+import java.util.StringTokenizer;
+
+public class BOJ_15961 {
+    private static int N,d,k,c;
+    private static int[] sushi;
+    private static int result;
+    private static int[] choice;
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        d = Integer.parseInt(st.nextToken());
+        k = Integer.parseInt(st.nextToken());
+        c = Integer.parseInt(st.nextToken());
+        choice = new int[d+1];
+        sushi = new int[N];
+
+        for (int i = 0; i < N; i++) {
+            sushi[i] = Integer.parseInt(br.readLine());
+        }
+
+        slide();
+
+        System.out.println(result);
+    }
+
+    static void slide() {
+        int left = 1;
+        int right = k;
+        int cnt = 0;
+
+        /* 초기 결과값 세팅*/
+        for(int i = 0 ; i < k; i++) {
+            if(choice[sushi[i]] == 0)
+                cnt++;
+            choice[sushi[i]]++;
+        }
+        result = choice[c] == 0 ? cnt+1 : cnt; // 쿠폰 초밥을 먹지 않았다면 결과 + 1
+        if(result == k+1) return;
+
+        while(left != N) {
+            if(choice[sushi[left-1]] == 1)  // 왼쪽 값이 중복되어있지 않을 때
+                cnt--;
+            choice[sushi[left-1]]--;
+            if(choice[sushi[right]] == 0)  // 오른쪽 값이 중복되어 있지 않을 때
+                cnt++;
+            choice[sushi[right]]++;
+
+            result = choice[c] == 0 ? Math.max(result,cnt+1) : Math.max(result,cnt);
+            if(result == k+1) break;
+
+            right = (right+1) % N;
+            left++;
+        }
+    }
+}