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

Input: Consider Input: Problem: how many diagonals does a polygon with 13 sides have , if one of its vertices does not connect to any diagonal ?

Output: 54


Input: Consider Input: Problem: a train running at the speed of 72 km / hr crosses a pole in 9 seconds . find the length of the train .

Output: 180 meter


Input: Consider Input: Problem: there is a church tower 150 feet tall and another catholic tower at a distance of 350 feet from it which is 200 feet tall . there is one each bird sitting on top of both the towers . they fly at a constant speed and time to reach a grain in b / w the towers at the same time . at what distance from the church is the grain ?


Output: 150 meters