static void Main(string[] args)
{
Group groupA = new Group("DevJava");
Student studentA = new Student("Petro", "Gavrilyk", 25);
Student studentB = new Student("S***n", "Werytin", 20);
studentB.SetStageEvolution(StageEvolution.Demo1);
groupA.AddStudent(studentA);
groupA.AddStudent(studentB);
Console.Write(groupA.ConvString());
Console.Read();
}