import java.util.*;

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