using System;               

public class Program

{

    public static void Main()

    {

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

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

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

​

        Lice(a,b,c);

    }

    static void Lice(double a, double b, double c)

    {

        Console.WriteLine(2*(a*b)+(a*c)+(b*c));

​

    }

}

​