When Do We Finish?

In this problem you are given the starting time of an event and its duration. All you have to do is to say when the event ends.

Input consists of a number of lines, each line representing an event. The last line of input will be 00:00 00:00 – do not process this line. Each event is represented by two times separated by a space. Each time is in the format hh:mm. The first time is the start time of the event, the second time is its duration. For the start time, a legal time using a 24 hour clock will be supplied. For the duration, the minutes will be from 0 to 59 inclusive, but the hours may be from 0 to 96 inclusive.

For each line of input, produce one line of output containing a single time, also in the format hh:mm, being the end time of the event as a legal 24 hour time. If this time is not on the same day as the start time, the time will be in the format hh:mm +n, where n is the number of days after the starting day.