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(input) {
  var X = parseInt(input.split(/\n| /)[0]);
  var N = parseInt(input.split(/\n| /)[1]);
  var p = input.split("\n")[1].split(" ").map(n => parseInt(n));
 

  if (N === 0) {
    console.log(X);
  } else {
    for(i = X-1; i >= -100; i--){
      if(p.indexOf(i) === -1){
        console.log(i);
        break;
      } else if( p.indexOf(2 * X - i) === -1){
          console.log(2 * X - i);
          break;
        }
      }
  }
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));