from Queue import *

def main():
  q = Queue()
  q.enqueue(5)
  q.enqueue(3)
  print(q)
  print(len(q))
  print(q.dequeue())
  print(q.is_empty())
  print(q.dequeue())
  print(q.is_empty())
  print(q.dequeue())
  q.enqueue(7)
  q.enqueue(9)
  print(q.first())
  q.enqueue(4)
  print(len(q))
  print(q.dequeue())

main()