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.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 pn[] = new int[N];
      for(int i=0; i<N; i++){
        pn[i] = scan.nextInt();
      }
      int ans1 = X;
      int ans2 = X;
      int x = X;
      
      while(true){
        for(int i=0; i<N; i++){
           if(x == pn[i]){
             ans1 = 200;
             break;
           }else
             ans1 = x;
        }
        if(ans1 == x)
          break;
        x -= 1;
      }
      x = X;
      while(true){
        for(int i=0; i<N; i++){
           if(x == pn[i]){
             ans2 = 200;
             break;
           }else
             ans2 = x;
        }
        if(ans2 == x)
          break;
        x += 1;
      }
      
      if(X-ans1 > ans2-X)
        System.out.println(ans2);
      else
        System.out.println(ans1);
   }
}