The task is to generate the correct answer for a given math problem.

Ex Input:
Problem: a man can do a piece of work in 7 days , but with the help of his son , he can finish it in 3 days . in what time can the son do it alone ?

Ex Output:
4 1 / 5


Ex Input:
Problem: a is half good a work man as b and together they finish a job in 14 days . in how many days working alone b finish the job ?

Ex Output:
21


Ex Input:
Problem: it is currently 8 : 12 pm . at what time in the morning was it exactly 205,106 minutes ago ?

Ex Output:

9 : 4