#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
int n, a[102];
void solve() {
  int res = 0;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  reverse(a, a + n);
  for (int i = 0; i < n; i++) res += (n - i) * a[i];
  cout << res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int t = 1;
  while (t--) {
    solve();
  }
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  return 0;
}
