#include <bits/stdc++.h>
int main() {
  int a[1005];
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", &a[i]);
  int sum = 0;
  for (int i = 0; i < n; i++) sum += a[i];
  printf("%d", sum - n);
}
