func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int r, c, n, mnm, x, y, ret = 0;     cin >> r >> c >> n >> mnm;     vector<vector<int> > mapa(r, vector<int>(c, 1));     for (int i = 0; i < n; i++) {       cin >> x >> y;       mapa[x - 1][y - 1] = 2;     }     for (int i = 1; i <= r; i++) {       for (int j = 1; j <= c; j++) {         for (int k = 0; k < r - (i - 1); k++) {           for (int l = 0; l < c - (j - 1); l++) {             int cnt = 0;             for (int m = 0; m < i; m++) {               for (int n = 0; n < j; n++) {                 if (mapa[k + m][l + n] == 2) cnt++;               }             }             if (cnt >= mnm) ret++;           }         }       }     }     cout << ret << endl;   }   