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: Runtime Error)

import java.lang.Math.abs

private fun readLn() = readLine()!!
private fun readInt() = readLn().toInt()
private fun readStrings() = readLn().split(" ")
private fun readInts() = readStrings().map(String::toInt)
private fun readStrings2() = readLn().split("").filter { it.isNotEmpty() }
private fun readInts2() = readStrings2().map(String::toInt)
private fun initArray(n:Int, v:String) = Array(n) { v }
private fun initIntArray(n:Int, v:Int) = IntArray(n) { v }

fun main(args: Array<String>) {
    val (X, N) = readInts()
    val p = readInts().sorted()

    if (N == 0) {
        println(X)
    } else {
        for (i in 0 until N) {
            val t1 = X - i
            val t2 = X + i
            if (!p.contains(t1)) {
                println(t1)
                break
            } else if (!p.contains(t2)) {
                println(t2)
                break
            }
        }
    }
}