func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAX = 4040;   map<int, int> cnt1;   map<int, int> cnt2;   pair<int, int> a[200020];   int main() {     int ans = 0;     int n;     cin >> n;     for (int i = 0; i < n; i++) {       cin >> a[i].first >> a[i].second;       cnt1[a[i].first + a[i].second]++;       cnt2[a[i].first - a[i].second]++;     }     for (int i = 0; i < n; i++) {       int curx = a[i].first;       int cury = a[i].second;       ans += cnt2[curx - cury] - 1 + cnt1[curx + cury] - 1;     }     cout << ans / 2 << endl;   }   