{2}matches exactly 2 characters from the set below:
Athe literal A (6510 / 1018 / 4116) (case sensitive)
Wthe literal W (8710 / 1278 / 5716) (case sensitive)
Mthe literal M (7710 / 1158 / 4D16) (case sensitive)
Sthe literal S (8310 / 1238 / 5316) (case sensitive)
\da digit