#include <bits/stdc++.h>

[[nodiscard]] static inline constexpr int_fast32_t solve(const int_fast32_t X, const int_fast32_t Y, const int_fast32_t L) noexcept
{
	if (Y < 0)
		return (std::abs(X) + L - 1) / L + (std::abs(Y) + L - 1) / L + 2;
	else if (X != 0)
		return (std::abs(X) + L - 1) / L + (std::abs(Y) + L - 1) / L + 1;
	else
		return (std::abs(X) + L - 1) / L + (std::abs(Y) + L - 1) / L;
}

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	
	int_fast32_t X, Y, L;
	std::cin >> X >> Y >> L;

	std::cout << solve(X, Y, L) << '\n';
	return 0;
}