using System;

using System.Collections.Generic;

public class Dice {

    protected Random rnd;

    public Dice(int seed) {

        rnd = new Random(seed);

    }

    public virtual int Next() {

        return rnd.Next(1,7);       

    }

}

​

public class FairRandom : Dice {

    private int lastNumber = 3;

    public FairRandom(int seed) : base(seed){}

    public override int Next() {

        int num;

        if (lastNumber == 6) {

            num = rnd.Next(1,3);

        }

        else if (lastNumber == 1) {

            num = rnd.Next(5,7);

        }

        else {

            num = rnd.Next(1,7); 

        }

        lastNumber = num;

        return num;

    }

}

public class Program

{

    public static void Main()

    {

        FairRandom rnd = new FairRandom(1);

        for (int i=0;i<100;i++)

            Console.WriteLine(rnd.Next());

    }

}