1a 1b 1c 1d 2a 2b 2c 2d 3a 3b 3c 3d 4a 4b 4c 4d 5a 5b 5c 5d 6a 6b 6c 6d 7a 7b 7c 7d 8a 8b 8c 8d 9a 9b 9c 9d 10a 10b 10c 10d 11a 11b 11c 11d 12a 12b 12c 12d 13a 13b 13c 13d 14a 14b 14c 14d 15a 15b 15c 15d 16a 16b 16c 16d 17a 17b 17c 17d 18a 18b 18c 18d 19a 19b 19c 19d 20a 20b 20c 20d 21a 21b 21c 21d