import java.util.Scanner;

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

		int n = sc.nextInt(), s = 0, r;
		for(int i = 0; i < n; i++){
		 s += sc.nextInt();
		}
		r = sc.nextInt();
		System.out.println(s-r);
	}
}