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.*;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int x = sc.nextInt();
        int n = sc.nextInt();
        int l = -1;
        int r = 1;

        
        ArrayList<Integer> array = new ArrayList<>();
        for(int i = 0; i < 100; i++){
            array.add(i+1);
        }
        for(int i = 0; i < n; i++){
            array.set( array.indexOf(sc.nextInt()), 0);
        }
        if(array.get(x-1) == 0){
            while(true){
                if(array.get(x-1 + l) != 0 && array.get(x-1 + r) != 0){
                    System.out.println(array.get(x-1 + l));
                    break;
                }else if(array.get(x-1 + l) != 0 || array.get(x-1 + r) != 0){
                    System.out.println(array.get(x-1 + l) != 0 ? array.get(x-1 + l) : array.get(x-1 + r) != 0 ? array.get(x-1 + r) : "a");
                    break;
                }else {
                    l--;
                    r++;
                }
                
            }
        }else{
            System.out.println(x);
        }
        
    }
}