You are given a math word problem and you are supposed to apply a single mathematical operators like addition, subtraction, multiplication or division on the numbers embedded in the text to answer the following question and then only report final the numerical answer.

Ex Input:
Melanie had 30 baseball cards , and 9 were torn . Sara bought 18 of Melanie 's baseball cards . How many baseball cards does Melanie have now ?

Ex Output:
12


Ex Input:
Diana starts with 65 bottle caps . 4 are eaten by a hippopotamus . How many bottle caps does Diana end with ?

Ex Output:
61


Ex Input:
Billy has 62 crayons . 52 are eaten by a hippopotamus . How many crayons will Billy have ?

Ex Output:

10