import java.util.Scanner;

public class No369 {

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