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 C# (Mono-mcs 6.8.0.105) (judge verdict: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;

namespace ABC170C
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = Console.ReadLine().Split(' ');
            var x = int.Parse(input[0]);
            var n = int.Parse(input[1]);
            if (n > 0)
            {
                var numbers = Console.ReadLine().Split(' ');
                var numList = new List<int>();

                for (var i = 1; i <= 100; i++)
                {
                    if (!numbers.Contains(i.ToString()))
                    {
                        numList.Add(i);
                    }
                }

                var abs = 100;
                for (var i = 1; i <= numList.Count(); i++)
                {
                    if (Math.Abs(numList[i] - x) < abs)
                    {
                        abs = Math.Abs(numList[i] - x);
                    }
                    else
                    {
                        Console.WriteLine(numList[i - 1]);
                        break;
                    }
                }
            }
            else
            {
                Console.WriteLine(x);
            }
        }
    }
}