#include <bits/stdc++.h>

using namespace std;

int main(){
    int n;
    cin >> n;
    int miles = 0;
    vector<int> calories(n);
    for(int calories_i = 0; calories_i < n; calories_i++){
       cin >> calories[calories_i];
    }
    // your code goes here
    for(int i=0;i<n;i++){
        miles = miles + pow(i,2)*calories[i];
    }
    cout<<miles;
    return 0;
}