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