package main

import . "fmt"

func main() {
	r:=int64(1)
	for {
		var c rune
		Scanf("%c",&c)
		if c<65 {
			Println(r)
			return
		}
		if c=='L' {
			r*=2
		} else {
			r=r*2+1
		}
	}
}