#include <iostream>
#include <iomanip>
#include <cstdint>
#include <cmath>

static inline constexpr double solve(const uint_fast32_t A, const uint_fast32_t B, const uint_fast32_t C) noexcept
{
	const double s = (A + B + C) / 2;
	const double S = sqrt(s * (s - A) * (s - B) * (s - C));

	return S / s;
}

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

	uint_fast32_t A, B, C;
	std::cin >> A >> B >> C;

	std::cout << std::fixed << std::setprecision(10) << solve(A, B, C) << '\n';
	return 0;
}