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

Ex Input:
Problem: a man can do a piece of work in 7 days , but with the help of his son , he can finish it in 3 days . in what time can the son do it alone ?

Ex Output:
4 1 / 5


Ex Input:
Problem: in what time will a train 50 m long cross an electric pole , it its speed be 360 km / hr ?

Ex Output:
0.5


Ex Input:
Problem: a computer is programmed to multiply consecutive even integers 2 * 4 * 6 * 8 * … * n until the product is divisible by 1881 , what is the value of n ?

Ex Output:

114