func_code_string: #include <bits/stdc++.h>   int n;   int main() {     int i;     long long ans, sumx, sumy, x, y;     scanf( %d , &n);     ans = sumx = sumy = 0;     for (i = 0; i < n; i++) {       scanf( %I64d%I64d , &x, &y);       ans += (long long)x * x * n + y * y * n;       sumx += x;       sumy += y;     }     printf( %I64d , ans - sumx * sumx - sumy * sumy);   }   