using System;
using System.Linq;

class Program
{
    public void Solve()
    {
        int kokudou = 1;

        string LR = Console.ReadLine();

        foreach (char c in LR.ToCharArray())
        {
            kokudou *= 2;
            if (c == 'R') { kokudou++; }
        }

        Console.WriteLine(kokudou);
    }

    static void Main()
    {
        var solver = new Program();
        solver.Solve();
    }
}