#include <bits/stdc++.h>
using namespace std;
const long long LLINF = 9223372036854775807;
const int MOD = 1000000007;
int main() {
  int N;
  cin >> N;
  int A[N];
  for (int i = 0; i < (int)N; i++) cin >> A[i];
  int result = 0;
  for (int i = 0; i < (int)N; i++) result += A[N];
  result -= N;
  cout << result << endl;
  return 0;
}
