import java.util.Scanner;

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