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

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            long ret = 1;
            for (int i = 0; i < s.Length; i++)
            {
                ret *= 2;
                if (s[i] == 'R') ret++;
            }
            Console.WriteLine(ret);
        }
    }
}