#include <bits/stdc++.h>

[[nodiscard]] static inline constexpr uint_fast64_t solve(const uint_fast64_t N, const uint_fast32_t M) noexcept
{
	return N / 1000 / M * 1000;
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	
	uint_fast64_t N;
	uint_fast32_t M;
	std::cin >> N >> M;

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