func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<pair<int, int> > vec;   int grid1[2050], grid2[2050];   int main() {     int n;     cin >> n;     int r = 0, c = 0;     long long ans = 0;     for (int i = 1; i <= n; i++) {       int x, y;       cin >> x >> y;       ans += grid1[x + y];       grid1[x + y]++;       ans += grid2[x - y + 1000];       grid2[x - y + 1000]++;     }     cout << ans << endl;     return 0;   }   