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: Accepted)

<?php
  $input = trim(fgets(STDIN));
  list($n, $m) = explode(' ', $input);
	$max = $n;
	$min = $n;

  $input = trim(fgets(STDIN));
  $num = explode(' ', $input);
	foreach($num as $value){
      $nums[] = abs($value);
    }
  $result = null;
	while(true){
    	if(in_array($max, $nums) === true){
        	$max = $max + 1;
        }else{
        	$result[] = $max;
        }
      	if(in_array($min, $nums) === true){
        	$min = $min - 1;
        }else{
        	$result[] = $min;
        }
      if(isset($result)){
      	break;
      }
    }
echo min($result);
?>