Class Structure Class Structure FormNumber of Class 14 (1A, 1B, 1C, 1D) 24 (2A, 2B, 2C, 2D) 34 (3A, 3B, 3C, 3D) 44 (4A, 4B, 4C, 4D) 54 (5A, 5B, 5C, 5D) 64 (6A, 6B, 6C, 6D)