input: Write a function that calculates the nth smart number.
  assert smartNumber(1) == 30
  assert smartNumber(50) == 273
  assert smartNumber(1000) == 2664
output: def smartNumber(n):
      def is_smart(num):
          count = 0
          for i in range(1, num + 1):
              if num % i == 0:
                  count += 1
          return count % 2 == 0
  
      index = 0
      num = 1
      while index < n:
          if is_smart(num):
              index += 1
          if index < n:
              num += 1
      return num