import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = Integer.parseInt(scanner.next());
        int answer = 0;
        for (int i = 0; i < n; i++) {
            answer += Integer.parseInt(scanner.next());
        }
        int yukiAnswer = Integer.parseInt(scanner.next());

        System.out.println(answer - yukiAnswer);
    }
}