func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e5 + 5;   const int M = 1e9 + 7;   const int INF = 2e9 + 5;   const int rx[8] = {-1, 0, 1, 0, 1, 1, -1, -1};   const int ry[8] = {0, -1, 0, 1, 1, -1, 1, -1};   mt19937 gen(chrono::high_resolution_clock::now().time_since_epoch().count());   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int n;     cin >> n;     vector<pair<long long, long long> > a(n);     long long sumx = 0;     long long sumy = 0;     for (int i = 0; i < n; i++) {       cin >> a[i].first >> a[i].second;       sumx += a[i].first;       sumy += a[i].second;     }     long long res = 0;     for (int i = 0; i < n; i++) {       res += (n - 1) * a[i].first * a[i].first - a[i].first * (sumx - a[i].first);       res += (n - 1) * a[i].second * a[i].second -              a[i].second * (sumy - a[i].second);     }     cout << res;     return 0;   }   