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

Ex Input:
Problem: the average of first 17 even numbers is ?

Ex Output:
18


Ex Input:
Problem: two trains travel in opposite directions at 36 kmph and 45 kmph and a man sitting in slower train passes the faster train in 12 seconds . the length of the faster train is

Ex Output:
270 m


Ex Input:
Problem: the average of the marks of 30 students in a class is 45 . if the marks of each student are doubled , find the new average ?

Ex Output:

90