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) {
  input = input.split("\n");
  let target = parseInt(input[0].split(" ")[0]);
  let zerocheck = parseInt(input[0].split(" ")[1]);
  if (zerocheck == 0) {
    console.log(target);
  } else {
    let str = input[1].split(" ");
    for (let i = 0; i < str.length; i++) {
      let num = parseInt(str[i]);
      str[i] = target - num;
    }
    for (let ite = 1; ite <= 100; ite++) {
      const isp = str.indexOf(ite);
      const isn = str.indexOf(-ite);
      if (isp != -1) {
        console.log(target - isp);
        break;
      } else if (isn != -1) {
        console.log(target - isp);
        break;
      }
    }
  }
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));