import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		if(!sc.hasNext()) {
			System.out.println(1);
			return;
		}
		String s = sc.next();
		int n = s.length();
		int ans = 1;
		for(int i = 0 ; i < n ; i++) {
			if(s.charAt(i) == 'R') {
				ans = ans * 2 + 1;
			} else {
				ans = ans * 2;
			}
		}
		System.out.println(ans);
 	}
}