Given a series of arrays, with each individual array containing the time of the alarm set and the sleep duration, return what time to sleep.

Examples

bed_time(["07:50", "07:50"]) ➞ ["00:00"]
# The second argument means 7 hours, 50 minutes sleep duration.

bed_time(["06:15", "10:00"], ["08:00", "10:00"], ["09:30", "10:00"]) ➞ ["20:15", "22:00", "23:30"]
# The second argument of each sub array means 10 hours sleep duration.

bed_time(["05:45", "04:00"], ["07:10", "04:30"]) ➞ ["01:45", "02:40"]
# Sleep duration can be different among the arrays.

Notes

• Times should be given in 24-hrs (i.e. "23:25" as opposed to "11:25PM").
• Return an array of strings.