import java.util.Scanner;

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