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

class Program
{
    static void Main(string[] args)
    {
        string s = Console.ReadLine();
        int load = 1;

        for (int i = 0; i < s.Length; i++)
        {
            load *= 2;

            if (s[i] == 'R')
            {
                load++;
            }
        }

        Console.WriteLine(load);
        Console.Read();
    }
}