func_code_string: #include <bits/stdc++.h>   using namespace std;   int read() {     int x = 0, f = 1;     char ch = getchar();     while (ch <  0  || ch >  9 ) {       if (ch ==  - ) f = -1;       ch = getchar();     }     while (ch >=  0  && ch <=  9 ) {       x = x * 10 + ch -  0 ;       ch = getchar();     }     return x * f;   }   int n, m, K, mp[1005][1005];   int main() {     memset(mp, 0, sizeof(mp));     n = read();     m = read();     K = read();     for (int i = 1; i <= K; i++) {       int x = read(), y = read();       mp[x][y] = 1;       if (mp[x + 1][y] && mp[x][y + 1] && mp[x + 1][y + 1]) {         cout << i << endl;         return 0;       }       if (mp[x + 1][y] && mp[x][y - 1] && mp[x + 1][y - 1]) {         cout << i << endl;         return 0;       }       if (mp[x - 1][y] && mp[x][y + 1] && mp[x - 1][y + 1]) {         cout << i << endl;         return 0;       }       if (mp[x - 1][y] && mp[x][y - 1] && mp[x - 1][y - 1]) {         cout << i << endl;         return 0;       }     }     cout << 0 << endl;     return 0;   }   