Problem:
Score : 300 points

Problem Statement

Given are an integer X and an integer sequence of length N: p_1, \ldots, p_N.

Among the integers not contained in the sequence p_1, \ldots, p_N (not necessarily positive), find the integer nearest to X, that is, find the integer whose absolute difference with X is the minimum. If there are multiple such integers, report the smallest such integer.

Constraints

1 \leq X \leq 100

0 \leq N \leq 100

1 \leq p_i \leq 100

p_1, \ldots, p_N are all distinct.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

X N
p_1 ... p_N

Output

Print the answer.

Sample Input 1

6 5
4 7 10 6 5

Sample Output 1

8

Among the integers not contained in the sequence 4, 7, 10, 6, 5, the one nearest to 6 is 8.

Sample Input 2

10 5
4 7 10 6 5

Sample Output 2

9

Among the integers not contained in the sequence 4, 7, 10, 6, 5, the ones nearest to 10 are 9 and 11. We should print the smaller one, 9.

Sample Input 3

100 0

Sample Output 3

100

When N = 0, the second line in the input will be empty. Also, as seen here, X itself can be the answer.

Solution in C (Clang 10.0.0) (judge verdict: Accepted)

#include <stdio.h>

int main(void)
{   
    int x,n;
    scanf("%d %d",&x,&n);

    int p[n];
    int i,j;
    for(i=0;i<n;i++){
        scanf("%d",&p[i]);
    }

    int ans_sei=x,ans_fu=x;
    while(1){

        for (j = 0; j < n; j++)
        {
            if (ans_fu == p[j])
            {
                ans_fu--;
                break;
            }
        }
        if (j == n)
        {
            printf("%d\n", ans_fu);
            return 0;
        }

        for(i=0;i<n;i++){
            if(ans_sei==p[i]){
                ans_sei++;
                break;
            }
        }
        if(i==n){
            printf("%d\n",ans_sei);
            return 0;
        }

        
    }


    return 0;
}