$ python3 llil.py big1.txt big2.txt big3.txt > out1.txt
collect time            :    5.2 s
sort_via_cmp_to_key time:   17.7 s
sort+format time        :   17.7 s
total processing time   :   22.9 s
output time             :    3.5 s
total time              :   26.4 s