import java.util.Scanner;

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