Time Punch Sorter

I often have to deal with a series of time punches which come formatted in 12-hour time and listed in reverse order.  I wrote this script to convert the times to 24-hour time and put them in order.  It assumes these sequences all occur on the same day.

The expected input format is timestamps that basically look like 1:23 AM or 01:23 PM, and these are collected in pairs, regardless of line breaks.