(1) A person is guilty of manufacturing methamphetamine when he knowingly and unlawfully: (a) Manufactures methamphetamine; or (b) With intent to manufacture methamphetamine possesses two (2) or more chemicals or two (2) or more items of equipment for the manufacture of methamphetamine. (2) Manufacture of methamphetamine is a Class B felony for the first offense and a Class A felony for a second or subsequent offense.