import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int sum = 0;
    for(int i = 0;i < N;i++){
      int a = sc.nextInt();
      sum += a;
    }
    System.out.println(sum-N);
  }
}
