using System;

public class Hello
{
    public static void Main()
    {
        var ans = 1;
        var s = Console.ReadLine().Trim();
        for (int i = 0; i < s.Length; i++)
        {
            ans *= 2;
            if (s[i] == 'R') ans++;
        }
        Console.WriteLine(ans);
    }
}