func_code_string: #include <bits/stdc++.h>   const int inf = 1e9 + 7;   const int md = 1e9 + 7;   const double eps = -1e5;   using namespace std;   int n, ans, x, y;   bool a[1001][1001];   bool isin(int x, int y) { return x > 0 && x <= 1000 && y > 0 && y <= 1000; }   int main() {     cin >> n;     for (int i = 0; i < n; i++) {       cin >> x >> y;       a[x][y] = true;     }     for (int x = 1; x <= 1000; x++)       for (int y = 1; y <= 1000; y++)         if (a[x][y]) {           for (int xx = x, yy = y; isin(xx, yy); xx--, yy--) ans += a[xx][yy];           ans--;           for (int xx = x, yy = y; isin(xx, yy); xx++, yy--) ans += a[xx][yy];           ans--;           for (int xx = x, yy = y; isin(xx, yy); xx--, yy++) ans += a[xx][yy];           ans--;           for (int xx = x, yy = y; isin(xx, yy); xx++, yy++) ans += a[xx][yy];           ans--;         }     cout << ans / 2;   }   