import java.util.*;

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