import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String iStr = sc.nextLine();

        long route = 1;
        for (int i = 0; i < iStr.length(); i++) {
            route <<= 1;
            if (iStr.charAt(i) == 'R') route++;
        }
        System.out.println(route);
    }
}