diff --git a/AtCoder/ABC241/C/C.cpp b/AtCoder/ABC241/C/C.cpp
new file mode 100644
index 00000000..9ae38aec
--- /dev/null
+++ b/AtCoder/ABC241/C/C.cpp
@@ -0,0 +1,61 @@
+#include <iostream>
+#include <string>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1005;
+
+int n;
+std::string g[N];
+
+bool check(int x, int y) {
+    if (x + 5 < n) {
+        int cnt = 0;
+        for (int i = x; i <= x + 5; i++) {
+            if (g[i][y] == '.') cnt++;
+        }
+        if (cnt <= 2) return true;
+    }
+    if (y + 5 < n) {
+        int cnt = 0;
+        for (int i = y; i <= y + 5; i++) {
+            if (g[x][i] == '.') cnt++;
+        }
+        if (cnt <= 2) return true;
+    }
+    if (x + 5 < n && y + 5 < n) {
+        int cnt = 0;
+        for (int i = 0; i <= 5; i++) {
+            if (g[x + i][y + i] == '.') cnt++;
+        }
+        if (cnt <= 2) return true;
+    }
+    if (x + 5 < n && y - 5 >= 0) {
+        int cnt = 0;
+        for (int i = 0; i <= 5; i++) {
+            if (g[x + i][y - i] == '.') cnt++;
+        }
+        if (cnt <= 2) return true;
+    }
+    return false;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin >> n;
+    for (int i = 0; i < n; i++) {
+        cin >> g[i];
+    }
+    for (int i = 0; i < n; i++) {
+        for (int j = 0; j < n; j++) {
+            if (check(i, j)) {
+                cout << "Yes" << endl;
+                exit(0);
+            }
+        }
+    }
+    cout << "No" << endl;
+    return 0;
+}