import java.util.Scanner;


public class Main_yukicoder104 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        char[] s = sc.nextLine().toCharArray();
        int ret = 1;
        for (int i = 0; i < s.length; i++) {
        	ret <<= 1;
        	if (s[i] == 'R') {
        		ret |= 1;
        	}
        }

        System.out.println(ret);
        
        sc.close();
    }
}