using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


class BitFlipper
{
    static void Main()
    {

        ulong num = ulong.Parse(Console.ReadLine());
        string initialNumber = Convert.ToString((long)num, 2).PadLeft(64, '0');

        StringBuilder lastNumber = new StringBuilder(initialNumber);

        for (int i = 0; i < initialNumber.Length; i++)
        {
            if ((initialNumber[i] == initialNumber[i + 1]) && (initialNumber[i + 1] == initialNumber[i + 2]))
            {
                if (initialNumber[i] == '1')
                {
                    lastNumber[i] = lastNumber[i + 1] = lastNumber[i + 2] = '0';
                    i+= 2;
                }

                if (initialNumber[i] == '0')
                {
                    lastNumber[i] = lastNumber[i + 1] = lastNumber[i + 2] = '1';
                    i+= 2;
                }
            }

            if (i > 61)
            {
                break;
            }
        }

        string finalNumber = lastNumber.ToString();
        ulong result = Convert.ToUInt64(finalNumber, 2);
        Console.WriteLine(result);
    }
}