func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int r, c, n, k;     cin >> r >> c >> n >> k;     int x[n], y[n], res = 0, xi, yi;     for (int i = 0; i < n; i++) {       cin >> xi >> yi;       x[i] = xi - 1;       y[i] = yi - 1;     }     for (int i = 0; i < r; i++) {       for (int j = 0; j < c; j++) {         for (int i2 = i; i2 < r; i2++) {           for (int j2 = j; j2 < c; j2++) {             int violasenimg = 0;             for (int v = 0; v < n; v++) {               if (i <= x[v] && x[v] <= i2 && j <= y[v] && y[v] <= j2)                 violasenimg++;             }             if (violasenimg >= k) res++;           }         }       }     }     cout << res << endl;   }   