import java.util.Scanner;

class Difference{

	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();
		}

		int yuki = scan.nextInt();

		int sa = sum - yuki;
		
		System.out.println(sa);
	}
}