//#include <atcoder/all>
#include <bits/stdc++.h>
#include <cmath>
using namespace std;
//using namespace atcoder;
using ll = long long;
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
using Graph = vector<vector<ll>>;

int main() {
	ll an=1;
	string S;
	cin>>S;
	rep(i,S.size()){
		an=an*2+(S[i]=='R');
	}
	cout<<an<<endl;
	
}