Original classes

Potions is taught by Severus Snape
Transfiguration is taught by Minerva McGonagall
Defense Against the Dark Arts is taught by Remus Lupin

Adding some classes

Potions is taught by Severus Snape
Transfiguration is taught by Minerva McGonagall
Defense Against the Dark Arts is taught by Remus Lupin
Divination is taught by Sybil Trelawney
Care of Magical Creatures is taught by Rubeus Hagrid

Removing the new classes

Potions is taught by Severus Snape
Transfiguration is taught by Minerva McGonagall
Defense Against the Dark Arts is taught by Remus Lupin