class Stack:

def __init__(self):

self.stack = []

def push(self, item):

self.stack.append(item)

def pop(self):

last = self.stack[-1]

self.stack.pop()

return last

def peek(self):

return self.stack[-1]

def isEmpty(self):

return not self.stack

class MyQueue:

def __init__(self):

self.first_stack = Stack()

self.second_stack = Stack()

def enqueue(self, item):

self.first_stack.push(item)

def dequeue(self):

if self.second_stack.isEmpty():

while self.first_stack.stack:

item = self.first_stack.pop()

self.second_stack.push(item)

last = self.second_stack.pop()

return last

def peek(self):

if self.second_stack.isEmpty():

while self.first_stack.stack:

item = self.first_stack.pop()

self.second_stack.push(item)

last = self.second_stack.peek()

return last

def isEmpty(self):

empty = self.first_stack.isEmpty() and self.second_stack.isEmpty()

return empty

q = MyQueue()

q.enqueue(5)

q.enqueue(25)

q.enqueue(30)

print(q.peek())

print(q.dequeue())

print(q.dequeue())

print(q.dequeue())

print(q.isEmpty())

q.enqueue(70)

print(q.peek())