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 Kotlin (1.3.71) (judge verdict: Wrong Answer)

import kotlin.math.abs

fun main(args: Array<String>) {
    val line = readLine()!!.trim()
    val (x: Int, n: Int) = line.split(" ").map {it.toInt()}
    val ps: List<Int> = if (n > 0) {
        val line2 = readLine()!!.trim()
        line2.split(" ").map {it.toInt()}.take(n)
    } else {
        listOf()
    }

    val pset = ps.toSet()
    var result: Int = 500
    var min: Int = 500
    for (j in (1..100)) {
        if (abs(x - j) < min && !pset.contains(j)) {
            result = j
            min = abs(x - j)
        }
    }

    println("${result}")
}