using System;

public class Program

{

    public static void Main()

    {

        Random rand = new Random();

        Console.WriteLine("Класс А\n");

        for(int i  = 0; i < 20; i++){

        int first = rand.Next(127) + 1;

            int second = rand.Next(256);

        int third = rand.Next(256);

        int four = rand.Next(256);

        Console.WriteLine("10."+ second  + "." + third + "." + four  );

        }

        Console.WriteLine("\nКласс В\n");   

        for(int i  = 0; i < 20; i++){

                int first = rand.Next(63) + 128;

            int second = rand.Next(256);

        int third = rand.Next(256);

        int four = rand.Next(256);

            Console.WriteLine(first + "." + second  + "." + third + "." + four  );

        }

            Console.WriteLine("\nКласс C\n");   

        for(int i  = 0; i < 20; i++){

                int first = rand.Next(31) + 193;

            int second = rand.Next(256);

        int third = rand.Next(256);

        int four = rand.Next(256);

            Console.WriteLine(first + "." + second  + "." + third + "." + four  );

        }

    }

}