import java.util.Scanner;
public class Main{
	private static Scanner sc=new Scanner(System.in);
	public static void main(String args[])throws Exception{
		int n=sc.nextInt(),counter=0;
		for(int i=0;i<n;i++)counter+=sc.nextInt();
		int ans=sc.nextInt();
		System.out.println(counter-ans);
	}
}