A - You should output ARC, though this is ABC.

https://atcoder.jp/contests/abc255/submissions/32372992

AtCoder/ABC255/A/A.cpp

@@ -0,0 +1,24 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int r, c, a[10][10];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> r >> c;
+
+    for (int i = 1; i <= 2; i++) {
+        for (int j = 1; j <= 2; j++) {
+            cin >> a[i][j];
+        }
+    }
+
+    cout << a[r][c] << endl;
+
+    return 0;
+}