---

using System;

class Task1
{
    static void Main()
    {
        Console.Write("Введите k: ");
        double k = double.Parse(Console.ReadLine());

        double z = 2 * k * k + 1;

        if (k > 0)
            Console.WriteLine($"k > 0, z = {z}");
        else if (k < 0)
            Console.WriteLine($"k < 0, z = {z}");
        else
            Console.WriteLine($"k = 0, z = {z}");
    }
}