#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
    ll n,a[200010],i;
    cin >> n;
    for(i=0;i<n;i++){
        cin >> a[i];
    }
    ll ans=0;
    for(i=0;i<n;i++){
        ans+=(i+1)*(n-i)*a[i];
    }
    cout << ans << endl;
}