#include <bits/stdc++.h>
using namespace std;
int main() {
  freopen("modulo.in", "r", stdin);
  freopen("modulo.out", "w", stdout);
  int n, tmp;
  int sum = 0;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &tmp);
    sum += tmp;
  }
  printf("%d", sum - n);
  fclose(stdin);
  fclose(stdout);
  return 0;
}
