// yukicoder: No.369 足し間違い
// 2019.4.15 bal4u

#include <stdio.h>

//// 高速入力
#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif
int in()   // 整数の入力（負数に対応）
{
	int n = 0, c = gc();
	if (c == '-') {
		c = gc();
		do n = 10 * n + (c & 0xf), c = gc(); while (c >= '0');
		return -n;
	}
	do n = 10 * n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int main()
{
	int N, s;
	N = in();
	s = 0; while (N--) s += in();
	printf("%d\n", s - in());
	return 0;
}