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

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string S = Console.ReadLine();
            int now = 1;
            for(int i=0;i<S.Length;i++)
            {
                string temp = S.Substring(i, 1);
                if(temp=="R")
                {
                    now = now * 2 + 1;
                }
                else
                {
                    now = now * 2;
                }
            }
            Console.WriteLine(now);
        }
    }
}