#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

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