# coding=utf-8
#author:        4N
#createtime:    2021/5/17
#email:         nheweijun@sina.com


class Queue:
    def __init__(self):
        self.items = []
    def init(self,items):
        self.items = items
    def empty(self):
        return self.items == []
    def append(self, item):
        self.items.insert(0,item)
    def pop(self):
        return self.items.pop()
    def size(self):
        return len(self.items)
    def __str__(self):
        return self.items.__str__()