#include<stdio.h>
#include<string.h>
#include<math.h>

#define NIL -1
#define zizyou(a,b) pow(((a)-(b)),2.0)

int main()
{
    int target, length;
    int ini_array[100];
    int answer_num = 0;
    int answer_abs = 20000;
    int answer_array[101];

    scanf("%d %d", &target, &length);

    for (int i = 0; i<=101; i++)
    {
        answer_array[i] = i;
    }

    for (int i = 0; i<length; i++)
    {
        scanf("%d", &ini_array[i]);
        answer_array[ini_array[i]] = NIL;
    }

    for (int i = 0; i<101; i++)
    {
        if (answer_array[i] == NIL)
        {
            continue;
        }

        if (zizyou(target, answer_array[i]) < answer_abs)
        {
            answer_abs = zizyou(target, answer_array[i]);
            answer_num = answer_array[i];
        }
    }

    printf("%d", answer_num);


    return 0;
}