import java.io.*;

public class Run {
    public static void main (String arg[]) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String S = br.readLine();
        int Road = 1;
        for (int i = 0; i < S.length(); i++) {
            Road *= 2;
            if (S.charAt(i)=='R') Road++;
        }
        System.out.println(Road);
    }
}