Given a side length `n`, traveling only right and down how many ways are there to get from the top left corner to the bottom right corner of an `n by n` grid?
Your mission is to write a program to do just that!
Add code to `route(n)` that returns the number of routes for a grid `n by n` (if n is less than 1 return 0).
Examples:
    -100 -> 0
    1 -> 2
    2 -> 6
    20 -> 137846528820
Note: 
you're traveling on the edges of the squares in the grid not the squares themselves.
PS.If anyone has any suggestions of how to improve this kata please let me know.
from math import factorial as f
routes=lambda n:f(n*2) // (f(n)*f(n)) if n>0 else 0
from math import factorial as f
routes=lambda n:f(n*2) // (f(n)*f(n)) if n>0 else 0