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: Accepted)

using System;

namespace ABC170C
{
    class Program
    {
        static void Main(string[] args)
        {
            var aa = Console.ReadLine().Split(" ");
            int x, n ,z;
            int f = 0;
            z = 9999999;
            x = int.Parse(aa[0]);n = int.Parse(aa[1]);
            int[] p = new int[n + 1];
            var b = Console.ReadLine().Split(" ");
            for(int i = 1;i <= n ;i++)
            {
                p[i] = int.Parse(b[i - 1]);
            }

            for(int i = 0;z == 9999999; i++)
            {
                f = 0;
                for (int c = 1; c <= n; c++)
                {
                    if (x + i == p[c])
                        f = 1;
                }

                if (f == 0)
                    z = x + i;


                f = 0;

                for (int c = 1; c <= n; c++)
                {
                    if (x - i == p[c])
                        f = 1;
                }

                if (f == 0)
                    z = x - i;


            }

            Console.WriteLine(z);
           
        
          


        }
    }
}