using System;

public class Program

{

    public static double a,b,c,p;

    public static double area,operacion;

    public static void Main()

    {

            a = Convert.ToUInt32(Console.ReadLine());

            b = Convert.ToUInt32(Console.ReadLine());

            c = Convert.ToUInt32(Console.ReadLine());

            p = Convert.ToUInt32(Console.ReadLine());

        if ( p < a)

            Console.WriteLine("P no es mayor que a, b o c.");

        else if (p < b)

            Console.WriteLine("P no es mayor que a, b o c.");

​

        else if (p < c)

            Console.WriteLine("P no es mayor que a, b o c.");

        else

        {

            p = ( (a + b + c) / 2 );

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

            Console.WriteLine("p es igual " + p);

            Console.WriteLine("area es igual a " + area);

        }  

    }

}