#include <stdio.h>
#include <stdlib.h>

int main() {
	int n = 1, i = 0;
	char s[30];
	s[0] = '\0';

	gets(s);

	while (s[i] != '\0') {
		n *= 2;
		if (s[i] == 'R')
			n++;
		i++;
	}

	printf("%d\n", n);

	return EXIT_SUCCESS;
}