import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		int gokei = 0;
		
		for(int i=0;i<N;i++) {
			gokei+=sc.nextInt();
		}
		System.out.println(gokei-N);
		
	}
}