A1Bottom level first position from front end. A2Bottom level second position from front end. A3Bottom level third position from front end. A4Bottom level fourth position from front end A5Bottom level fifth position from front end. A6Bottom level sixth position from front end. A7Bottom level seventh position from front end A8Bottom level eighth position from front end A9Bottom level ninth position from front end AXBottom level twelfth position from front end AYBottom level eleventh position from front end AZBottom level tenth position from front end B1Second level first position from front end. B2Second level second position from front end. B3Second level third position from front end. B4Second level fourth position from front end. B5Second level fifth position from front end. B6Second level sixth position from front end. B7Second level seventh position from front end. B8Second level eighth position from front end B9Second level ninth position from front end BXSecond level twelfth position from front end BYSecond level eleventh position from front end BZSecond level tenth position from front end C1Third level first position from front end. C2Third level second position from front end. C3Third level third position from front end. C4Third level fourth position from front end. C5Third level fifth position from front end. C6Third level sixth position from front end. C7Third level seventh position from front end. C8Third level eighth position from front end C9Third level ninth position from front end CXThird level twelfth position from front end CYThird level eleventh position from front end CZThird level tenth position from front end