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

Ex Input:
Problem: mary can do a piece of work in 26 days . rosy is 30 % more efficient than mary . the number of days taken by rosy to do the same piece of work is ?

Ex Output:
20


Ex Input:
Problem: a statue is being carved by a sculptor . the original piece of marble weighed 180 kg . in the first week 28 percent is cut away . in the second week 18 percent of the remainder is cut away . in the third week the statue is completed when 20 percent of the remainder is cut away . what is the weight of the final statue ?

Ex Output:
85 kg


Ex Input:
Problem: how long does a train 105 m long running at the speed of 68 km / hr takes to cross a bridge 90 m length ?

Ex Output:

10.7 sec