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: Runtime Error)

import java.util.Scanner;
import java.math.*;
import java.util.Arrays;

public class Main

{
    public static void main(String[] args){
        Scanner sc =new Scanner(System.in);
        int x=sc.nextInt();
        int n=sc.nextInt();
        int count1=0;
        int count2=0;
        int plus=0;
        int minus=0;
        int flg=0;
        int[] list = new int[n];
        list[0]=x;
        for(int i=1; i<list.length; i++){
            list[i]=sc.nextInt();
        }
        while(true){
            for(int i=0; i<list.length; i++){
                if(list[i]==x+plus){
                    plus++;
                }
                count1++;
            }
            if(count1>plus){
                break;
            }
            while(true){
                for(int i=0; i<list.length; i++){
                    if(list[i]==x+minus){
                        minus--;
                    }
                    count2--;
                }
                if(count2<minus){
                    break;
                }
                flg=Math.abs(plus)-Math.abs(minus);
                if(flg>=0){
                    System.out.println(x+minus);
                }else if(flg<0){
                    System.out.println(x+plus);
                }
            }
        }}}