import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String s = sc.next(); if(s.isEmpty()) { System.out.println(1); return; } 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); } }