#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000


int main(){
	
	string s = "";
	cin>>s;
	
	int ans = 1;
	rep(i,s.size()){
		ans *= 2;
		if(s[i]=='R')ans++;
	}
	
	cout<<ans<<endl;
	return 0;
}