func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     map<int, int> mp;     map<int, int> np;     for (int i = 1; i <= n; i++) {       int x, y;       cin >> x >> y;       int p = y - x;       int q = y + x;       mp[p]++;       np[q]++;     }     map<int, int>::iterator it;     int box = 0;     for (it = mp.begin(); it != mp.end(); it++) {       int g = it->second;       box += (g * (g - 1)) / 2;     }     for (it = np.begin(); it != np.end(); it++) {       int g = it->second;       box += (g * (g - 1)) / 2;     }     cout << box << endl;   }   