/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{

    public static void main (String[] args) throws java.lang.Exception
    {
        // your code goes here
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        String[] lines = br.readLine().split(" ");
        int v = Integer.parseInt(br.readLine());
        
        int sum = 0;
        for(String st:lines){
            sum += Integer.parseInt(st);
        }
        System.out.println(sum-v);
    }
}