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: Accepted)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int x = nextInt(scanner);
        int n = nextInt(scanner);
        List<Integer> p = new  ArrayList<>();
        for (int i = 0; i < n; i++) {
            p.add(nextInt(scanner));
        }
        int i = 0;
        if (!p.contains(x)) {
            System.out.println(x);
            return;
        }
        while (true) {
            if (!p.contains(x - i)) {
                System.out.println(x - i);
                return;
            }
            if (!p.contains(x + i)) {
                System.out.println(x + i);
                return;
            }
            i++;
        }
    }

    private static int nextInt(Scanner scanner) {
        return Integer.parseInt(scanner.next());
    }

    private static long nextLong(Scanner scanner) {
        return Long.parseLong(scanner.next());
    }

    private static float nextFloat(Scanner scanner) {
        return Float.parseFloat(scanner.next());
    }

    private static double nextDouble(Scanner scanner) {
        return Double.parseDouble(scanner.next());
    }


}