func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int r, c, n, k;     scanf( %d%d%d%d n , &r, &c, &n, &k);     int a[r][c];     for (int i = 0; i < r; i++) {       for (int j = 0; j < c; j++) {         a[i][j] = 0;       }     }     int x, y;     for (int i = 0; i < n; i++) {       scanf( %d %d n , &x, &y);       a[x - 1][y - 1] = 1;     }     int ans = 0, lsum;     for (int r1 = 0; r1 < r; r1++)       for (int r2 = r1 + 1; r2 < r + 1; r2++)         for (int c1 = 0; c1 < c; c1++)           for (int c2 = c1 + 1; c2 < c + 1; c2++) {             lsum = 0;             for (int i = r1; i < r2; i++)               for (int j = c1; j < c2; j++) lsum += a[i][j];             if (lsum >= k) ans++;           }     printf( %d n , ans);     return 0;   }   