import java.util.Scanner;

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

	}
}