#include <stdio.h>

int main(void)
{
	int a[110] = { 0 };
	int x, n;
	int ans1 = 0, kyo=0;
	int f[110] = { 0 };
	scanf("%d%d", &x, &n);
	for (int i = 0; i < n; i++) {
		scanf("%d", &a[i]);
		f[a[i]] = 1;
	}

	for (int i = 1; i <= 100; i++) {
		if (i < x) {
			if (f[i] == 0) {
				ans1 = i;
				kyo = x - i;
			}
		}
		else if (x < i) {
			if (f[i] == 0 && kyo > i - x)
				ans1 = i;
		}

	}

	if (n==0)
		printf("%d\n", x);
    else if(ans1)
        printf("%d\n", ans1);

	return 0;
}