package yukicoder;

import java.util.Scanner;

public class yuki369 {
	
	public static void main(String[] args){
		
		//System.out.println("helloWorld");
		Scanner scan = new Scanner(System.in);
		int count = scan.nextInt();
		int[] countArr = new int [count];
		int addcount = 0;
		for (int i = 0; i < count; i++) {
			//countArr[count] = scan.nextInt();
			//addcount += countArr[count];
			addcount += scan.nextInt();
		}
		int yukians = scan.nextInt();
		//System.out.println("addcount" + addcount);
		//System.out.println("yukians" + yukians);
		System.out.println(addcount - yukians);
		
	}
}