new
empty 1
size 0
head0
push_front 13
empty 0
size 1
head
	retrieve 13
	next
	retrieve 13
exit
push_front 14
empty 0
size 2
head
	retrieve 14
	next
	retrieve 13
	next
	retrieve 14
exit
push_front 15
empty 0
size 3
head
	retrieve 15
	next
	retrieve 14
	next
	retrieve 13
	next
	retrieve 15
exit
push_front 16
empty 0
size 4
head
	retrieve 16
	next
	retrieve 15
	next
	retrieve 14
	next
	retrieve 13
	next
	retrieve 16
exit
push_back 12
empty 0
size 5
head
	retrieve 16
	next
	retrieve 15
	next
	retrieve 14
	next
	retrieve 13
	next
	retrieve 12
	next
	retrieve 16
exit
pop_front 16
empty 0
size 4
head
	retrieve 15
	next
	retrieve 14
	next
	retrieve 13
	next
	retrieve 12
	next
	retrieve 15
exit
pop_back 12
empty 0
size 3
head
	retrieve 15
	next
	retrieve 14
	next
	retrieve 13
	next
	retrieve 15
exit
pop_front 15
pop_back 13
pop_front 14
empty 1
size 0
head0
delete
summary
exit