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: Runtime Error)

import java.util.Scanner

import scala.io.StdIn._
object Main extends App {

  def read(): (Int, Array[Int]) = {
    val sc: Scanner = new Scanner(System.in)
    val x, n = sc.nextInt()
    val arr = Array.fill(n)(sc.nextInt)
    sc.close()
    (x, arr)
  }

  def solve(): Int = {
    val (x, arr) = read
    (1 to 100).diff(arr.toSeq).map { num =>
      (num, (x - num).abs)
    }.minBy { case (num, diff) => (diff, num) }._1
  }

  println(solve())

}