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 JavaScript (Node.js 12.16.1) (judge verdict: Wrong Answer)

function Main(arg) {
    var arg = arg.trim().split('\n');
    let x = Number(arg[0].split(' ')[0]);
    let n = arg[0].split(' ')[1];
    let p = arg[1];
    
    if( p === undefined || p.indexOf(x) < 0 ){
      console.log(x);
      return;
    }
    
    for(let i = 1; i < 100; i++){
      if(p.indexOf(`${x-1*i}`) < 0 ){
        console.log(x-1*i);
        return;
      } else if(p.indexOf(`${x+i}`) < 0 ){
        console.log(x+i);
        return;
      }
    }
    return;
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));