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 C++ (GCC 9.2.1) (judge verdict: Accepted)

/*
    @uthor: Amit Kumar
    user -->GitHub: drviruses ; CodeChef: dr_virus_ ; Codeforces,AtCoder,Hackerearth,Hakerrank: dr_virus;
*/
#include <bits/stdc++.h>
#include <chrono>
using namespace std;
using namespace std::chrono;
//#include <boost/multiprecision/cpp_int.hpp>
//namespace mp = boost::multiprecision;
//#define ln mp::cpp_int;
#define ll    long long
#define ld    long double
#define ull   unsigned long long
#define endl "\n"
ll google_itr = 1;
#define google(x) cout<<"\Case #"<<x<<"\:"
#define pi 3.14159265358979323846264338327950L

const ll mod = 1e9+7;
const ll inf = 1e18;

ll popcount(ll num){
    num = num - ((num >> 1) & 0x55555555);
    num = (num & 0x33333333) + ((num >> 2) & 0x33333333);
    return ((num + (num >> 4) & 0xF0F0F0F) * 0x1010101) >> 24;
}


void virus(){
        ll x,n;
        cin>>x>>n;
        ll left = x, right = x;
        
        vector<ll> arr(n);
        for(auto &i:arr) cin>>i;
        while(true){
            if(find(arr.begin(),arr.end(),left) == arr.end()){
                cout<<left;
                return;
            }
            else left--;
            if(find(arr.begin(),arr.end(),right) == arr.end()){
                cout<<right; return;
            }
            else right++;
        }
}


int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    
  /*#ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif*/

    ll t=1;
    //cin>>t;
    while(t--){
           auto start = high_resolution_clock::now();
           virus();
           auto stop = high_resolution_clock::now();
           auto duration = duration_cast<seconds>(stop - start);
         //cout << "Time: "<<duration.count()<<endl;
        //your code goes here
    }
    return 0;
}