Description
Fiona commutes to work each day. If there is no rush-hour traffic, her commute time is 2 hours. However, there is often rush-hour traffic.
Specifically, rush-hour traffic occurs from 07:00 (7am) until 10:00 (10am) in the morning and 15:00 (3pm) until 19:00 (7pm) in the afternoon.
During rush-hour traffic, her speed is reduced by half.
She leaves either on the hour (at XX:00), 20 minutes past the hour (at XX:20), or 40 minutes past the hour (at XX:40).
Given Fiona’s departure time, at what time does she arrive at work?
Input
The input will be one line, which contains an expression of the form HH:MM,
where HH is one of the 24 starting hours (00, 01, ..., 23) and MM is one of the three possible departure minute times (00, 20, 40).
Output
Output the time of Fiona’s arrival, in the form HH:MM.