#include<bits/stdc++.h>
#define int long long
#define endl "\n"
#define MAXN 100005	
#define inf 1e18
using namespace std;
int a[MAXN], f[MAXN], g[MAXN];
int n, sum=0;
signed main() {
	if (fopen("temp.inp", "r")){
		freopen("temp.inp", "r", stdin);
		freopen("temp.out", "w", stdout);
	}
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	cin>>n;
	for (int i=1; i<=n; i++){
		cin>>a[i];
		sum+=a[i]*(n-i+1)*(i);
	}
	cout<<sum;
	
}