import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		
		int correctAns = 0;
		for (int i = 0; i < n; i++) {
			correctAns += sc.nextInt();
		}
		
		int yukiAns = sc.nextInt();
		
		System.out.println(correctAns - yukiAns);
		
		sc.close();
	}
}