package yukicoder;
import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		new Main().solve();
	}
	void solve(){
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		int[] a=new int[n];
		long correct_sum=0;
		for(int i=0;i<n;i++)correct_sum+=sc.nextLong();
		long sum=sc.nextLong();
		System.out.println(-sum+correct_sum);
	}
}