using System;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        // No.104 国道

        char[] S = Console.ReadLine().ToCharArray();
        int nowRoad = 1;

        for (int i = 0; i < S.Length; i++)
        {
            nowRoad*=2;
            if ('R'.Equals(S[i])) nowRoad++;
        }

        Console.WriteLine(nowRoad);
    }
}