#define _USE_MATH_DEFINES
#include <iostream>
#include <cmath>

constexpr double PI = 3.1415926535;

int main()
{
	using namespace std;

	long double a, b, x;

	cin >> a >> b >> x;

	long double S = x / a;

	long double B = a * b / 2;

	if(S > B)
	{
		long double n = 2 * S / a - b;
		long double t = atanl((b - n) / a));
		cout << t * 180 / M_PI << endl;
	}
	else
	{
		long double n = 2 * S / b;
		long double t = atanl(b / n);
		cout << t * 180 / M_PI << endl;
	}
}