#include <bits/stdc++.h>
using namespace std;

int main() {
	int n; cin >> n;
	vector<long long> a(n);
	for (int i = 0; i < n; i++) cin >> a[i];
	long long ans = 0;
	for (int i = 0; i < n; i++) {
		ans += a[i] * (i+1) * (n-i);
	}
	cout << ans << endl;
}