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
$stdin = file_get_contents('php://stdin');
$stdin = explode("\n", trim($stdin));
list($x, $n) = explode(' ', $stdin[0]);
$p = explode(' ', $stdin[1]);
$max = max($p);
$max = max($x, $max) + 1;
$min = NULL;
$ans = NULL;

for ($i = 1; $i <= $max; $i++) {
  if (in_array($i, $p)) {
    continue;
  }
  $abs = abs($i - $x);
  if ($min === NULL || $min > $abs) {
    $min = $abs;
    $ans = $i;
  } 
} 
echo $ans;