#include <iostream>
#include <fstream>

using namespace std;
const double PI = 3.1415 / 6;

int main()
{
	int iter = 0, s = 1, i = 0;
	ofstream f;
	f.open("output.txt");
	double sum = 0, result = PI;
	double res2 = 42.0;
	while (((sum-res2) >= 0.000001) || ((sum-res2) <= -0.000001))
	{
		sum += result;
		cout << iter << ';' << sum << endl;
		f << sum << endl;
		iter++;
		i += 2;
		s *= -1;
		res2 = sum;
		result *= PI*PI*s / (36*i*i);
	}
	f.close();
	cin.get();
	return 0;
}