7 7 7
1
2
3
4
5
6
7
 4 2 8
1
3
4
2
3
4
1
2
 9 4 9
1
2
3
4
5
6
7
8
9
 7 5 7
1
2
3
4
5
6
7
 15 10 15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
 4 0 4
1
2
3
4
 12 2 12
1
2
3
4
5
6
7
8
9
10
11
12
 10 2 10
1
2
3
4
5
6
7
8
9
10
 7 4 7
1
2
3
4
5
6
7
 7 3 7
1
2
3
4
5
6
7

XXXXXXX
 ..XX.X.X
 ...X.X.XX
 .X.XXXX
 .X.X.X.X.XXXXXX
 ....
 .........X.X
 .......X.X
 .X.X.XX
 ...X.XX

#include <bits/stdc++.h>
using namespace std;
int x, n;
int a[150];
long long d(long long i) {
  if (i == 1)
    return a[i];
  else
    return (a[i] + (a[i] - 1) * (i - 1) + d(i - 1));
}
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  cout << d(n);
  return 0;
}
