import java.util.*;
public class Road{
	public static void main(String[] arg){
		Scanner sc = new Scanner(System.in);
		int n=0,res=1;
		String in="";
		if(sc.hasNext()){
			in = sc.next();
			n = in.length();
		}
		for(int i = 0;i<n;i++){
			if(in.charAt(i) == 'R'){
				res = res*2+1;
			}else{
				res = res*2;
			}
		}
		System.out.println(res);
	}
}