#include <iostream>
using namespace std;

double root(int n)
{
    double L, R, B;
    L = 0; R = n;

    while (fabs(R - L) > 0.00001)
    {
        B = (L + R) / 2;

        if ( B*B > n)
        {
            R = B;
        }
        else {
            L = B;
        }
    }
    return B;
}

double root_hf_div(double n, double L, double R)
{
    double B;

    if (fabs(R - L) < 0.00001)
    {
        return (L + R) / 2;
    }
    else
    {
        B = (L + R) / 2;

        if ((B * B) > n)
        {
            return root_hf_div(n, L, B);
        }
        else
        {
            return root_hf_div(n, B, R);
        }
    }
}

int main()
{
    setlocale(LC_ALL, "Russian");
	double n; cin >> n;

    cout << "Обычный: " << root(n) << endl;
	
    cout << "Рекурсивный: " << root_hf_div(n, 1, n) << endl;
}