/*
 * main.c
 *
 *  Created on: 2016/06/27
 *      Author: owner
 */

#include<stdio.h>

int main(void) {
	int kosu, kazu,kazu_, yuki,i;

	scanf("%d\n", &kosu);

	for (i = 0; i < kosu; i++) {
		scanf("%d", &kazu_);
		kazu = kazu + kazu_;
	}
	scanf("%d", &yuki);

	printf("%d", kazu - yuki);

	return 0;
}