#include <bits/stdc++.h>

[[nodiscard]] static inline constexpr uint_fast32_t solve(const std::string& S) noexcept
{
	uint_fast32_t ans = 1;
	for (const auto& s : S)
	{
		ans *= 2;
		if (s == 'R') ++ans;
	}

	return ans;
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	
	std::string S;
	S.reserve(30), std::getline(std::cin, S);

	std::cout << solve(S) << '\n';
	return 0;
}