#include <bits/stdc++.h>
#define int long long
using namespace std;
main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n, tong = 0, a[200005];
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
    }
    for (int i = 1; i <= n; i++)
    {
        tong += a[i] * (n - i + 1) * i;
    }
    cout << tong;
}