#include <bits/stdc++.h>

using namespace std;

#define task ""
#define pii pair<int,int>
#define inf 1e18
#define int long long
#define endl '\n'
#define all(v) (v).begin(),(v).end()

const int maxn = 2e5 + 5;
const int mod = 1e9 + 7;
const int hx[] = {-1, 1, 0, 0};
const int hy[] = {0, 0, -1, 1};

mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());

int n, a[maxn];

signed main(){
    if (fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    ios_base :: sync_with_stdio(0);
    cin.tie(0), cout.tie(0);

    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];

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

    return 0;
}