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

Ex Input:
Problem: tim came second in math . when his mother asked him how much he had scored , he answered that he got the sum of the first 12 even numbers . his mother immediately worked out the answer . how much had he scored in math ?

Ex Output:
156


Ex Input:
Problem: the population of a bacteria culture doubles every 2 minutes . approximately how many minutes will it take for the population to grow from 1,000 to 300,000 bacteria

Ex Output:
16


Ex Input:
Problem: pipe p can fill a tank in 3 hours , pipe q in 9 hours and pipe r in 18 hours . if all the pipes are open , in how many hours will the tank be filled ?

Ex Output:

2 hours