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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Scanner;
import java.awt.image.BandedSampleModel;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class Main {


    public static void main(String args[])
    {
        Scanner sc=new Scanner(System.in);
        int x = sc.nextInt();
        int n = sc.nextInt();
        int p=10000;
        int ans=10000;
        Map<Integer,Integer> map=new HashMap<>();
        int arr[] = new int[n];
        for(int i=0;i<n;i++)
        {
            arr[i]=sc.nextInt();
            map.put(arr[i],1);
        }

        for(int i=1000;i>=0;i--)
        {
            int k=i-x;
            if(k<0)
            {
                k=-k;
            }
            if((k<=p)&&map.get(i)==null)
            {
                ans=i;
                p=k;
            }
        }
        System.out.println(ans);

    }
}