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
fscanf(STDIN, "%d %d", $X, $N);
$p = fgets(STDIN);
$array = explode(" ", $p);


for ($i = -2; $i < 103; $i++) {
  $base[] = $i;
}


foreach ($base as $key => $val) {
  foreach ($array as $a) {
    if($val == $a){
      //削除実行

      unset($base[$key]);
    }
  }
}


$ans = 1000;
$sa = 1000;
foreach ($base as $key => $value) {
  if (abs($value - $X) < $sa) {
    $sa = abs($value - $X);
    $ans = $value;
  } elseif (abs($value - $X) === $sa) {
    if ($ans > $value) {
      $ans = $value;
    }
  }
}



print_r ($ans);
?>