Salt Bomb

After failing a chemistry exam, Cheolsu decided to play a trick on his chemistry teacher.

Cheolsu hid a homemade robotic arm on the teacher's desk. He wants to program it so that at a fixed moment the arm dumps a pile of salt into the water cup the teacher always drinks from.

Cheolsu knows the current time and the time the salt should drop, but he is bad at arithmetic and cannot work out the waiting time to enter into the arm. Given the two times, find how long the arm has to wait.

The first line contains the current time in hh:mm:ss format. The hour is between $0$ and $23$, the minute and the second are each between $0$ and $59$, and every value is padded to two digits.

The second line contains the salt drop time in the same format.

Print on one line the waiting time from the current time to the salt drop time, in hh:mm:ss format. Pad every value to two digits.

If the salt drop time is earlier than the current time, it refers to that time on the next day. The waiting time is at least $1$ second and at most $24$ hours, so print 24:00:00 when the two times are equal.