import java.util.Scanner;

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

		System.out.println(sum-N);
	}
}
