using System;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        int n = int.Parse(Console.ReadLine());
        int ans = 0;

        if (n % 2 == 0)
        {
            ans = n;
        }
        else
        {
            ans = n + 1;
        }

        Console.WriteLine(ans);
    }
}