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){
    const arr = input.split('\n');
    const XN = arr[0].split(' ').map(Number);
    if(XN[1] == 0){
        console.log(XN[0]);
        return;
    }
    const pn = arr[1].split(' ').map(Number);
    let diff = 999;
    let answer = 0;
    for(i=0; i<=100; i++){
        if(pn.indexOf(i)>=0) continue;
        if(Math.abs(XN[0]-i) < diff){
            diff = XN[0]-i;
            answer = i;
        }
    }
    console.log(answer);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));