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 (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>

int abs(int x){
    int out;
    if (x > 0){
        out = x;
    } else {
        out = -x;
    }
    return out;
}

int main(){
    int x, n;
    int i, j, k;
    int out = 0;
    scanf("%d %d", &x, &n);
    int list[n];
    for (i = 0; i < n; i++){
        scanf("%d", &list[i]);
    }
    if (n == 0){
        printf("%d", x);
    } else {
        for (i = 1; i <= 100; i++){
            k = 0;
            for (j = 0; j < n; j++){
                if ((x-i) == list[j]){
                    k = 1;
                    break;
                }
            }
            if (k == 0){
                out = x - i;
                break;
            } else {
                k = 0;
                for (j = 0; j < n; j++){
                    if ((x+i) == list[j]){
                        k = 1;
                        break;
                    }
                }
                if (k == 0){
                    out = x + i;
                    break;
                }
            }
        }
        printf("%d", out);
    }

    return 0;
}