text: #Greg Considine
  #Project Euler -- Problem 15
  
  def factorial(x):
    if x == 1:
      return x
    else:
      return x * factorial(x-1)
  
  def choose(x, y):
    return factorial(x)/(factorial(x-y) * factorial(y))
  
  gridWidth = 20
  print(choose(gridWidth * 2, gridWidth))
  
  '''
  I knew how to solve this problem right away because I've been doing similar 
  stuff in a math class.  I used a calculator to get the answer (40C20), but I
  figured I'd implement factorial and choose functions anyway to continue the 
  tradition of solving the problems with Python.
  '''
  