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)

object methods {
  def solver(): Unit = {

    val tempList: Seq[Seq[String]] = {
      for (line <- io.Source.stdin.getLines()) yield {
        line.split(' ').toSeq
      }
    }.toSeq
    val X: Int = tempList(0)(0).toInt
    val N: Int = tempList(0)(1).toInt

    val numList: Seq[Int] = if(N != 0) {
      tempList(1).map(_.toInt)
    } else {
      Seq()
    }

    // 0~101までで正数列が含まれない集合を求める
    val rangeList: Set[Int] = Range(0, 102).toList.toSet //これで0から101
    val diffRange: List[Int] = rangeList.diff(numList.toSet).toList
    val diffAbsRange: List[Int] = diffRange.map(x => (x-X).abs)
    val minIndex: Int = diffAbsRange.indexOf(diffAbsRange.min)
    val minOfRange: Int = diffRange(minIndex)


    println(minOfRange)
  }
}

object Main extends App {
  methods.solver()
}