using System;

using System.Text;

using System.Diagnostics;

public class Program

{

    public static void Main()

    {

        Bus.Init(0);

        Bus bus1 = new Bus(71);

        Console.WriteLine(Bus.FirstBusNumber);

    }

}

​

public class Bus

{

    public static int FirstBusNumber;

​

    public static void Init(int firstBusNumber)

    {

        FirstBusNumber = firstBusNumber;

    }

    public Bus(int routeNum)

    {

        if(FirstBusNumber<1)

           FirstBusNumber = routeNum;

    }

}