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

Ex Input:
Problem: a train crosses a bridge of length 200 m in 10 seconds and a lamp post on the bridge in 5 seconds . what is the length of the train in metres ?

Ex Output:
200 m

Ex Input:
Problem: a and b together can complete work in 6 days . a alone starts working and leaves it after working for 4 days completing only half of the work . in how many days it can be completed if the remaining job is undertaken by b ?

Ex Output:
12

Ex Input:
Problem: how many zeroes are there at the end of the number n , if n = 70 ! + 140 ! ?

Ex Output:
16