using System;

public class Program

{

    public static void Main()

    {

        char[] obsNames = new char[4] { 'A', 'B', 'C', 'V' };

        int[] obsParam = new int[4];

        for (int i = 0; i < obsParam.Length; i++)

        {

            Console.Write(obsNames[i] + "? ");

            obsParam[i] = int.Parse(Console.ReadLine());

        }

        int[] obsRes = ObvodObsah(obsParam);

        Console.WriteLine("Obvod = " + obsRes[0].ToString());

        Console.WriteLine("Obsah = " + obsRes[1].ToString());

    }

    public static int[] ObvodObsah(int[] obsP)

    {

​

        return new int[2] { obsP[0] + obsP[1] + obsP[2], (obsP[0] * obsP[3]) / 2 };

    }

}