package main

import (
	"fmt"
)

func main() {
	var n string
	count:=1
	fmt.Scanln(&n)
	for i:=0;i<len(n);i++{
		if n[i:i+1] == "R"{
			count += count+1
		}else{
			count += count
		}
	}
	fmt.Println(count)
}