#include<iostream>
#include<string>
#include<cmath>

using namespace std;

#define NMAX 1000000

int main(){

	string S;
	long long ans;
	long long pos;
	long long bmax,nmax;
	cin>>S;

	if(S.size()==0) cout<<"1"<<endl;
	else{
		if(S[0]=='R') ans=3;
		else ans=2;
		for(int i=1;i<S.size();i++){
			bmax=pow(2.0,i)-1;
			nmax=pow(2.0,i+1)-1;
			pos=ans-bmax;
			ans=nmax+1+2*(pos-1);
			if(S[i]=='R') ans++;
		}
	}

	cout<<ans<<endl;
}