#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int n;
	cin >> n;
	vector<int>v(n);
	for (int i = 0; i < n; i++) {
		cin >> v[i];
	}
	ll sum = 0;
	for (int i = 0; i < n; i++) {
		int left = (i + 1);
		int right = (n - i);
		sum += v[i] * (right * left);
	}
	cout << sum << endl;
}