import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		sc.close();
		char dir[] = s.toCharArray();
		int bunki = 1;
		int RoadCount = 1;
		int countR = 0;
		for (int i = 0; i < dir.length; i++) {
			bunki *=2;
			RoadCount+= bunki;
		}
		RoadCount -= bunki;
		for (int i = 0; i < dir.length; i++) {
			if(dir[i] == 'R'){
				bunki /= 2;
			}
		}
		System.out.println(RoadCount+bunki);
	}

}