import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		String s = sc.nextLine();
		if (s == null) {System.out.println(1);}
		else {
			long ans = 1;
			for (int i=0; i<s.length(); i++) {
				if (s.charAt(i)=='R') {ans = ans*2 + 1;}
				else {ans = ans*2;}
			}
			System.out.println(ans);
		}
	}
}