func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2000001;   vector<long long> d1(N), d2(N);   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     long long n;     cin >> n;     long long x, y;     for (long long i = 0; i < n; i++) {       cin >> x >> y;       d1[x + y]++;       d2[x - y + 1000]++;     }     long long sums = 0;     for (long long i = 0; i <= 2001; i++) {       sums += 1LL * (d1[i]) * (d1[i] - 1) / 2;       sums += 1LL * (d2[i]) * (d2[i] - 1) / 2;     }     cout << sums <<   n ;   }   