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 PHP (7.4.4) (judge verdict: Wrong Answer)

<?php 
 
 $a = explode(" ", fgets(STDIN));

if($a[1] == 0){
  echo $a[0]; 
  die();
}


 $b = explode(" ", fgets(STDIN));

 $base = $a[0];

 $baseplus = $a[0];
 $baseminus = $a[0];
 
 if(!in_array($base,$b)){
   echo $base;
   die();
 }


echo search($baseplus,$baseminus,$b);

function search( $baseplus,$baseminus, $b){
  

while(true){
  
  $baseminus--;
  
  if(!in_array($baseminus,$b)){
 	return $baseminus; 	 
  }  
  
  $baseplus++;
  if(!in_array($baseplus,$b)){
 	return $baseplus; 	 
 }  
  
  
  
  
  
}

}