C-PROM 2014 (PROBLEM 7 :TIME CLOCK)

PROBLEM 7 : TIME CLOCK

You need to compute the total time a worker has worked on a single calendar day given two timestamps of the form “HH:MM”. The numbers MM can be in the range of “00” to “59” while HH is in the range “01” through “12”. This is an archaic (old-fashioned) timestamp clock that doesn’t even record AM or PM values. The system has worked well in the past because no-one has ever worked longer than an 8 hour shift.

You can be assured that the two times are different and represent an employee checking in to work (on a calendar day) and checking out from work later on the exact same calendar day. You are to output the total time as “HH:MM”. If the accumulated work time is greater than 8 hours (in other words, 481 minutes or longer), then you are ordered to output “08:00” because this is the maximum time that the employee would be paid.

Input

The first line of the input contains an integer N (1 ≤ N ≤ 30), the number of test cases. The following line will contain pairs of timestamps representing the starting and ending time containing five characters of the form “HH:MM” where HH is in the range “01” and “12” while MM in the range “00” through “59”.

The input must be read from standard input.

Output

The output of the program should display the accumulated time as “HH:MM” on a single line by itself where HH represents the number of hours in the range “00” to “12” and MM represents the number of minutes in the range “00” and “59”.

The output must be written to standard output.