stack=[]

def pushit():

    stack.append(raw_input('Enter New String:').strip())

def popit():

    if len(stack)==0:

        print 'can not pop anything from a empty stack'

    else:

        print 'Remove[',repr(stack.pop()),']'

def viewstack():

    print stack

CMDs={'u':pushit,'o':popit,'v':viewstack}

def showmenu():

    pr="""

    p(U)sh

    p(O)p

    (V)iew

    (Q)uit

    Enter choice:"""

    while True:

        while True:

            try:

                choice=raw_input(pr).strip().lower()

            except (EOFError,KeyboardInterrupt,IndexError):

                choice='q'

            print '\nYou picked:[%s]' %choice

            if choice  not in 'uovq':

                print'Invaild option,try again'

            else:

                break

        if choice=='q':

            break

        CMDs[choice]()

if __name__=='__main__':

    showmenu()

queue=[]

def enQ():

    queue.append(raw_input('Please enter a new element:').strip())

def deQ():

    if len(queue)==0:

        print "Error: cannot pop anything from a empty queue"

    else:

        print 'Remove [',queue.pop(0),']'

def viewshow():

    print queue

CMDs={'e':enQ,'d':deQ,'v':viewshow}

def showmenu():

    pr='''

      (E)nQ

      (D)eQ

      (V)iewshow

      (Q)uit

      Enter your choice:

    '''

    while True:

        while True:

            try:

                choice=raw_input(pr).strip()[0].lower()

            except (EOFError,KeyboardInterrupt,IndexError):

                choice='q'

            print 'You picked [%s]' % choice

            if choice not in 'edvq':

                print 'Invail option, Try again'

            else:

                break

        if choice=='q':

            break

        CMDs[choice]()

if __name__=='__main__':

    showmenu()