06. Area of Figures

using System;

namespace Nums1_10
{
    class Program
    {
        static void Main(string[] args)
        {
            string figure = Console.ReadLine();

            if (figure.Equals("square"))
            {
                double strana1 = double.Parse(Console.ReadLine());
                Console.WriteLine($"{strana1 * strana1:F3}");
            }
            else if (figure.Equals("rectangle"))
            {
                double strana2 = double.Parse(Console.ReadLine());
                double strana3 = double.Parse(Console.ReadLine());
                Console.WriteLine($"{strana2 * strana3:F3}");
            }
            else if (figure.Equals("circle"))
            {
                double strana4 = double.Parse(Console.ReadLine());
                Console.WriteLine($"{Math.PI * (strana4 * strana4):F3}");
            }
            else
            {
                double strana5 = double.Parse(Console.ReadLine());
                double strana6 = double.Parse(Console.ReadLine());
                Console.WriteLine($"{0.5 * (strana5 * strana6):F3}");
            }

        }
    }
}