input: Write a function to determine whether a given number is even or odd. If the number is even, return "Even"; if the number is odd, return "Odd".
  assert even_or_odd(4)=='Even'
  assert even_or_odd(7)=='Odd'
  assert even_or_odd(0)=='Even'
  assert even_or_odd(-3)=='Odd'
  assert even_or_odd(-6)=='Even'
output: def even_or_odd(n):
      if n % 2 == 0:
          return "Even"
      else:
          return "Odd"