import java.util.Scanner;

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++) {
      sum += sc.nextInt();
    }

    System.out.println(sum - n);

  }
}