import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) {
		BufferedReader buff = new BufferedReader(new InputStreamReader(System.in));

		try {
			String str = buff.readLine();

			int line = 1;

			for(int i = 0; i < str.length(); ++i){
				line *= 2;
				char ch = str.charAt(i);
				if(ch == 'R'){
					line++;
				}
			}

			System.out.println(line);

		} catch (NumberFormatException e) {
			e.getStackTrace();
		} catch (IOException e) {
			e.getStackTrace();
		} catch (Exception e) {
			e.getStackTrace();
		}
	}
}