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: Runtime Error)

r=require("fs").readFileSync("/dev/stdin","utf8").split("\n");
[x,n]=r[0].split(" ").map(x => parseInt(x));
p=r[1].split(" ").map(x => parseInt(x));
max=Math.max(...p);
min=Math.min(...p);
s=Array.from(Array(max-min+3), (v,k) => min-1+k).filter(x => p.indexOf(x)<0);
i=0;
s.reduce(function(ac,cv,idx){
    d=Math.abs(cv-x);
    if(ac>d)
    {
        i=idx;
        return d;
    }
    return ac;
},Number.POSITIVE_INFINITY);
console.log(s[i]);