#include <iostream>
#include <cmath>
using namespace std;
 
int main(){
	string S;
	cin >> S;
	int now = 1;
	for(int i = 0; i < S.size(); i++){	
		now *= 2;
		if(S[i] == 'R'){
			now++;
		}
	}
	cout << now << endl;
}