#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, sum = 0;
  int A[n];
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> A[i];
    sum += A[i];
  }
  cout << sum - n << endl;
  return 0;
}
