#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
const double eps = 1E-7;
long long n, ans, a[200];
int main() {
  cin >> n;
  for (int(i) = 0; (i) < (n); ++(i)) cin >> a[i];
  ans = 0;
  for (int(i) = 0; (i) < (n); ++(i)) {
    ans += a[i];
    for (int j = i + 1; j < n; ++j) ans += a[j] - 1;
  }
  cout << ans << endl;
  return 0;
}
