#include <iostream>
#include <math.h>
using namespace std;


int main()
{
	string s;
	getline(cin,s);
	int c = pow(2,s.length());//左端の番号

	int t = pow(2,s.length());
	for (int i = 0; i < s.length(); ++i)
	{
		if(s.at(i)=='R'){
			c += t / 2;
		}else{
			t = t / 2;
		}
	}
	cout<<c<<endl;
	return 0;
}