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)

"use strict";

function Main(input) {
    // 1行目がinput[0], 2行目がinput[1], …に入る
    input = input.split("\n");
    let tmp = input[0].split(" ");
    let x = parseInt(tmp[0], 10);
    let n = parseInt(tmp[1], 10);
    let p = input[1].split(" ").map(str => parseInt(str, 10)); //p[0], ... , p[n-1]

    p.sort(compareFunc);    //配列nを昇順に並べる

    let nearX = x;
    let i = 0;

    while (1) {
        nearX = x - i;
        if (!p.includes(nearX)) {
            console.log('%d', nearX);
            return;
        }
        nearX = x + i;
        if (!p.includes(nearX)) {
            console.log('%d', nearX);
            return;
        }
        i++;
    }

}

function compareFunc(a, b) {
    return a - b;
}


Main(require("fs").readFileSync("/dev/stdin", "utf8"));