I need this done in C++ please.

Set Up: Starting in the top left corner of a 2 2 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner Directions: Compute the number of these types of routes through an n n grid for 1 n 20. Allow the user to choose n. (Hint: be careful of memory overflow issues.) Input: the size of the grid (ie: n-10 where the grid is n n) Output: the number of routes from the top left corner to the bottom right corner Extra Credit: allow the user to choose any n >1 Due Date: December 5 Revision Date: December 14