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);

  if ($n == 0) {
    echo $x;
    return;
  }

  $nums = explode(' ', str_replace("\n", '', fgets(STDIN)));
  $ans;

  $i = 0;
  while (1) {
    if (array_search($x - $i, $nums) === false) {
      $ans = $x - $i;
      break;
    } else if (array_search($x + $i, $nums) === false) {
      $ans = $x + $i;
      break;
    } else {
      $i++;
    }
  }

  echo $ans;