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: Wrong Answer)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

public class Main {
	public static void main (String[] args) throws IOException{
	    InputStreamReader reader = new InputStreamReader(System.in, StandardCharsets.UTF_8);
	    BufferedReader in = new BufferedReader(reader);
	    String[] str1 = in.readLine().split(" ");
	    int num1 = Integer.parseInt(str1[0]);
	    int num2 = Integer.parseInt(str1[1]);

	    if(num2==0) {
			System.out.println(num1);
	    }else {
		    String[] str2 =in.readLine().split(" ");
		    List<Integer> arrays = new ArrayList<Integer>();
		    for(int i = 0; i<num2; i++) {
		    	arrays.add(Integer.parseInt(str2[i]));
		    }
			if(!arrays.contains(num1)) {
				System.out.println(num1);
			}else {
				for(int i=1; i<num2+1; i++) {
					if(num1>0) {
					}
					if(arrays.contains(num1-i)) {
						System.out.println(num1-i);
						break;
					}else if(!arrays.contains(num1+i)) {
						System.out.println(num1+i);
						break;
					}
				}
			}
	    }
	}
}