using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter a =");

        double a = double.Parse(Console.ReadLine());

        Console.WriteLine("Enter b =");

        double b = double.Parse(Console.ReadLine());

        Console.WriteLine("Enter c =");

        double c = double.Parse(Console.ReadLine());

        double P = a+b+c;

        double p = P/2;

        float S = (float)(Math.Sqrt(p*(p-a)*(p-b)*(p-c)));

        Console.WriteLine("P = {0} and S = {1}",P,S);

    }

}