using System;

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

            if (fig == "square")
            {
                double a = 5;
                Console.WriteLine($"{a * a:f3}");
            }

            else if (fig == "rectangle")
            {
                double a = 7;
                double b = 2.5;
                Console.WriteLine($"{a * b:f3}");
            }
            else if (fig == "circle")
            {
                double r = 6;
                Console.WriteLine($"{r * r * Math.PI:f3}");
            }
            else if (fig == "triangle")
            {
                double side = 4.5;
                double h = 20;
                Console.WriteLine($"{side * h / 2:f3}");
            }

        }
    }
}