#include <stdio.h>

int main () {
  int n = 0;
  int a = 0;
  
  int res = 0;
  
  res = scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    res = scanf("%d", &a);
  }
  
  printf("%d\n", a-n);
  return 0;
}