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 lNum = 1;
		for (int i = 0; i < dir.length; i++) {
				lNum *= 2 ;
				if(dir[i] == 'R') lNum++;
		}
		System.out.println(lNum);
	}

}