import java.util.*;
public class ppp {
		
  public static void main(String[] args) {
	  Scanner sc=new Scanner(System.in);
	  char c[]=sc.next().toCharArray();
	  int n=1;
	  for(int i=0;i<c.length;i++){
		  n*=2;
		  if(c[i]=='R')n++;
	  }
	  System.out.println(n);
	 
  }}