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 Scala (2.13.1) (judge verdict: Accepted)

import java.util.Scanner

import scala.util.control.Breaks

object Main {

  def main(args: Array[String]): Unit = {
    val sc = new Scanner(System.in)
    val x = sc.nextInt()
    val n = sc.nextInt()

    val p = Set.fill(n)(sc.nextInt())

    var ans = x
    var dis = 0
    val b = new Breaks
    b.breakable {
      while (true) {
        if (!p.contains(ans - dis)) {
          ans = ans - dis
          b.break()
        } else if (!p.contains(ans + dis)) {
          ans = ans + dis
          b.break()
        } else {
          dis += 1
        }
      }
    }

    println(ans)

  }

}