input: Write a python function to classify numbers as even or odd.
  assert classifyNumber(3) == "odd"
  assert classifyNumber(4) == "even"
  assert classifyNumber(0) == "even"
  assert classifyNumber(-1) == "odd"
  assert classifyNumber(101) == "odd"
output: def classifyNumber(n):
      if n % 2 == 0:
          return "even"
      else:
          return "odd"