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.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
		// 整数の入力
        
        int x = sc.nextInt();
        
        int scnum = sc.nextInt();
        if(scnum == 0) System.out.println(x);System.exit(0);

        int[] p = new int[scnum];

        for(int i = 0;i < scnum;i++){
            p[i] = sc.nextInt();
        }

        Arrays.sort(p);

        int min = 200;
        int ans = -1; 
        int j = 0;
        for(int i = 0;i < 102;i++){
            if(i == p[j]){
                if(j < scnum){
                    j++;
                }
            }else if(Math.abs(i - x) < min){
                ans = i;
                min = Math.abs(i - x);
            }
        }
		// 出力
		System.out.println(ans);

    }
}