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: the area of a triangle is with base 10 m and height 5 m ?

Ex Output:
25


Ex Input:
Problem: x can finish a work in 25 days . y can finish the same work in 20 days . y worked for 12 days and left the job . how many days does x alone need to finish the remaining work ?

Ex Output: