func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 100005;   int n;   long long sol(long long* data) {     long long ans = 0, fang = 0, sum = 0;     for (int i = 1; i <= n; i++) {       ans += data[i] * data[i] * (i - 1);       ans -= sum * data[i] * 2;       ans += fang;       fang += data[i] * data[i];       sum += data[i];     }     return ans;   }   long long x[maxn], y[maxn];   int main() {     scanf( %d , &n);     for (int i = 1; i <= n; i++) scanf( %lld%lld , x + i, y + i);     sort(x + 1, x + n + 1);     sort(y + 1, y + n + 1);     cout << sol(x) + sol(y) << endl;   }   