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 main(){
        int i, x, n, left=103, right=103;
        scanf("%d %d", &x, &n);

        if(n==0){
                printf("%d", x);
                return 0;
        }

        int p[101]={0};
        int pp;

        for(i=0; i<n; i++){
                scanf("%d", &pp);
                p[pp]=1;
        }

        int count=0;

        for(i=0; i<101; i++){
                if(p[x+i]!=1){
                        right=x+i;
                        count++;
                }
                if(p[x-i]!=1){
                        left=x-i;
                        count++;
                }

                if((count!=0)&&(left>right)){
                        printf("%d", right);
                        return 0;
                }else if((count!=0)&&(right>left)){
                        printf("%d", left);
                        return 0;
                }

        }

        return 0;
}