*matches any number of characters from the set below:
Nthe literal N (7810 / 1168 / 4E16) (case sensitive)
Mthe literal M (7710 / 1158 / 4D16) (case sensitive)
Xthe literal X (8810 / 1308 / 5816) (case sensitive)
athe literal a (9710 / 1418 / 6116) (case sensitive)
bthe literal b (9810 / 1428 / 6216) (case sensitive)
\da digit