static void Main(string[] args)
        {
            while(n>=0 && n<1000)
            {
                nhap();
                if (kiemtra() == 1) xuat1();
                else if (kiemtra() == 2) xuat2();
                else xuat3();
                Console.Write("\n");
            }

            Console.ReadKey();
        }
        static int n;
        static int tram()
        {
            int hangtram = n / 100;
            return hangtram;
        }
        static int chuc()
        {
            int a = n / 10;
            int hangchuc = a % 10;
            return hangchuc;
        }
        static int donvi()
        {
            int hangdonvi = n % 10;
            return hangdonvi;
        }
        static void nhap()
        {
            Console.Write("Nhap N=");
            n = int.Parse(Console.ReadLine());
        }
        static int kiemtra()
        {
            string y = Convert.ToString(n);
            int x = y.Length;
            return x;
        }
        static void xuat1()
        {
            if (donvi() == 0) Console.Write("");
            if (donvi() == 1) Console.Write("mot");
            if (donvi() == 2) Console.Write("hai");
            if (donvi() == 3) Console.Write("ba");
            if (donvi() == 4) Console.Write("bon");
            if (donvi() == 5) Console.Write("nam");
            if (donvi() == 6) Console.Write("sau");
            if (donvi() == 7) Console.Write("bay");
            if (donvi() == 8) Console.Write("tam");
            if (donvi() == 9) Console.Write("chin");
        }
        static void xuat2()
        {

            if (chuc() == 1) Console.Write("muoi ");
            if (chuc() == 2) Console.Write("hai muoi ");
            if (chuc() == 3) Console.Write("ba muoi ");
            if (chuc() == 4) Console.Write("bon muoi ");
            if (chuc() == 5) Console.Write("nam muoi ");
            if (chuc() == 6) Console.Write("sau muoi ");
            if (chuc() == 7) Console.Write("bay muoi ");
            if (chuc() == 8) Console.Write("tam muoi ");
            if (chuc() == 9) Console.Write("chin muoi ");
            xuat1();
        }
        static void xuat3()
        {

            if (tram() == 1) Console.Write("mot tram ");
            if (tram() == 2) Console.Write("hai tram ");
            if (tram() == 3) Console.Write("ba tram ");
            if (tram() == 4) Console.Write("bon tram ");
            if (tram() == 5) Console.Write("nam tram ");
            if (tram() == 6) Console.Write("sau tram ");
            if (tram() == 7) Console.Write("bay tram ");
            if (tram() == 8) Console.Write("tam tram ");
            if (tram() == 9) Console.Write("chin tram ");
            xuat2();

        }