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)

object Main extends App{
  val sc = new java.util.Scanner(System.in)
  var a , b =sc.nextInt()
  if(b == 0) {print(a);sys.exit()}
  var c = List.fill(b)(sc.nextInt())
  if(c.indexOf(a) == -1){print(a);sys.exit()}
  c :+ a
  c = c.sorted
  var min = 0
  var max = 0
  if (c.indexOf(a) == 0){print(a-1);sys.exit()}
  min = c(c.indexOf(a) - 1)
  if(c.indexOf(a) != 4) {
    max = c(c.indexOf(a)+1)
  }else{
    max = 101
  }
  var i = a-1
  var j = a+1
  var ans = 0
  while (i == min){
    i-=1
    if(!(c.indexOf(min)-1 == -1)) {
      min = c(c.indexOf(min) - 1)
    }
  }
  while (j == max){
    j+=1
    if(!(c.indexOf(max)+1 > b-1)) {
      max = c(c.indexOf(max) + 1)
    }
  }
  var ia = a-i
  var ja = a-j
  if(ia >= a){print(0);sys.exit()}
  if(math.abs(ia)>math.abs(ja)){
    print(j)
  }else{
    print(i)
  }
}