#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>
using namespace std;
int x[100008];
int y[100008];

int main(){
	int n;
	cin>>n;
	if(n%2==0)cout<<n<<endl;
	else cout<<n+1<<endl;


	return 0;
}