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.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int X = scan.nextInt();
		int N = scan.nextInt();
		int[] p = new int[N];
		for(int i = 0; i < N; i++) {
			p[i] = scan.nextInt();
		}
		int upper = X+1;
		int lower = X-1;
		int ans = 0;

		ans = judge(N, p, X);

		while (ans == 0) {
			ans = judge(N, p, lower);
			if (ans != 0) {
				break;
			}
			ans = judge(N, p, upper);
			upper++;
			lower--;
		}

		System.out.println(ans);
	}

	public static int judge(int N, int[] p, int k) {
		int f = 0;
		int ans = 0;

		for(int i = 0; i < N; i++) {
			if (k == p[i]) {
				f++;
				break;
			}
		}
		if (f == 0) {
			ans = k;
		}
		return ans;

	}

}