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:
13 ducks are swimming in a lake . 20 more ducks come to join them . How many ducks are swimming in the lake ?

Ex Output:
33

Ex Input:
Steve has 46 oranges . He shares 4 with Patrick . How many oranges will Steve have ?

Ex Output:
42

Ex Input:
Sam grew 4 watermelons , but the rabbits ate 3 watermelons . How many watermelons does Sam have left ?

Ex Output:
1