4 Class Categories X 3 Base Classes per = 12.
Warrior (Fighter, Barbarian, Martial Adept), Rogue (Thief, Acrobat, Ranger), Mystic (Cleric, Druid, Warlock),
Wizard (Mage, Psychic, Swordmage/"Magus")
12 Base Classes X 3 Sub-(or "Expert")classes per = 36
Warrior: Fighter: Default Fighter...