Non-Capturing Group(?:[01]?[0-9]|[2][0-3]) 1st Alternative[01]?[0-9] ?matches at most one character from the set below:
0the literal 0 (4810 / 608 / 3016)
1the literal 1 (4910 / 618 / 3116)
0-9one character from 0 (4810) to 9 (5710)
2the literal 2 (5010 / 628 / 3216)
0-3one character from 0 (4810) to 3 (5110)
:the literal : (5810 / 728 / 3A16)
0-5one character from 0 (4810) to 5 (5310)
0-9one character from 0 (4810) to 9 (5710)
\s*any whitespace character, repeated any number of times
pthe literal p (11210 / 1608 / 7016) (case insensitive)
athe literal a (9710 / 1418 / 6116) (case insensitive)
\.?optionally matches the literal . (4610 / 568 / 2E16)
mthe literal m (10910 / 1558 / 6D16) (case insensitive)
\ban ASCII word boundary
\.?optionally matches the literal . (4610 / 568 / 2E16)