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)

function Main(input) {
    input = input.split("\n");
    const tmp = input[0].split(" ");
    const x = parseInt(tmp[0], 10);
    const n = parseInt(tmp[1], 10);
    if(n === 0){
        console.log(x);
        return;
    }
    const p_str = input[1].split(" ");
    let p = [];
    for(let i = 0;i < n ; i++){
        p[i] = parseInt(p_str[i], 10);
    }

    p.sort(
        function(a,b){
            return (a < b ? -1 : 1);
        }
    );
 
    for(let i = 0;i < 100 ; i++){
        if( p.indexOf(x - i) === -1 ){
            console.log(x - i);
            return;
        }
        if( p.indexOf(x + i) === -1 ){
            console.log(x + i);
            return;
        }
             
    }
   

}
 
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));