#include <bits/stdc++.h>

namespace MyLib
{
	template<uint_fast32_t max_value>
	[[nodiscard]] static inline constexpr std::array<bool, max_value + 1> make_is_prime() noexcept
	{
		std::array<bool, max_value + 1> is_prime = { false };
		for (uint_fast32_t i = 2; i <= max_value; ++i)
			is_prime[i] = true;
	
		for (uint_fast32_t i = 2; i * i <= max_value; ++i)
			if (is_prime[i]) [[unlikely]]
				for (uint_fast32_t j = i * i; j <= max_value; j += i)
					is_prime[j] = false;
	
		return is_prime;
	}
}

[[nodiscard]] static inline constexpr uint_fast64_t solve(const uint_fast64_t N) noexcept
{
	static constexpr std::array<bool, 100'001> is_prime = MyLib::make_is_prime<100'000>();
	uint_fast64_t ans = 0;
	for (uint_fast32_t i = 2; static_cast<uint_fast64_t>(i) * i <= N; ++i)
		if (is_prime[i])
			for (uint_fast64_t term = static_cast<uint_fast64_t>(i) * i; term <= N; term *= i)
				ans += term;

	return ans;
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	
	uint_fast64_t N;
	std::cin >> N;

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