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: Accepted)

const Main = input => {
    input = input.split("\n");
    const xn = input[0].split(" ").map(value => parseInt(value, 10));

    const x = xn[0];
    const n = xn[1];

    let near;
    if(n === 0) {
        //nが0のときはx自身を答えにする
        near = x;
    } else {
        const p = input[1].split(" ").map(value => parseInt(value, 10));

        //pに存在する整数を除いた1~100までのリスト
        const list = [];
        for(let i = 0; i <= 101; i++) {
            if(p.includes(i)) continue;
            list.push(i);
        }

        near = 0;
        list.forEach(value => {
            if(Math.abs(value - x) < Math.abs(near - x)) {
                near = value;
            }
        })
    }

    console.log(near);
}
 
Main(require("fs").readFileSync("/dev/stdin", "utf8"));