package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanLines)
	sc.Scan()
	s := sc.Text()
	ans := 1
	for i := 0; i < len(s); i++ {
		ans *= 2
		if s[i] == 'R' {
			ans++
		}
	}
	fmt.Println(ans)
}