diff --git a/24xxx/24919.cpp b/24xxx/24919.cpp
new file mode 100644
index 00000000..085c24a3
--- /dev/null
+++ b/24xxx/24919.cpp
@@ -0,0 +1,26 @@
+#include <cmath>
+#include <iostream>
+#include <vector>
+using namespace std;
+
+void solve(int idx) {
+  int n; cin >> n;
+  vector<vector<char>> v(2*n, vector<char>(2*n));
+  for (int i=0; i<2*n; i++) for (int j=0; j<2*n; j++) cin >> v[i][j];
+
+  int a = 0, b = 0;
+  for (int i=0; i<n; i++) for (int j=0; j<n; j++) a += (v[i][j] == 'I');
+  for (int i=n; i<2*n; i++) for (int j=n; j<2*n; j++) a -= (v[i][j] == 'I');
+  for (int i=0; i<n; i++) for (int j=n; j<2*n; j++) b += (v[i][j] == 'I');
+  for (int i=n; i<2*n; i++) for (int j=0; j<n; j++) b -= (v[i][j] == 'I');
+  cout << "Case #" << idx << ": " << abs(a) + abs(b) << "\n";
+}
+
+int main(void) {
+  ios::sync_with_stdio(false);
+  cin.tie(nullptr);
+
+  int t; cin >> t;
+  for (int i=1; i<=t; i++) solve(i);
+  return 0;
+}
\ No newline at end of file