static void Main(string[] args)
UInt64 niemYet, chietKhau;
Console.WriteLine("Tinh gia mat hang");
Console.Write(" - Nhap gia niem yet: ");
niemYet = UInt64.Parse(Console.ReadLine());
Console.Write(" - Nhap gia chiet khau: ");
chietKhau = UInt64.Parse(Console.ReadLine());
VAT = (niemYet - chietKhau) * 0.01;
giaBan = niemYet - chietKhau + VAT;
Console.WriteLine(" - Gia ban san pham la: {0}", giaBan);