_un
bun
_ub
tub
_ug
pug
_un
sun
_ug
tug
_um
plum
_ut
hut
_ud
mud
_up
cup
_un
run
_ug
mug
_ut
nut
_ut
cut
_ug
bug
_uck
luck
_ug
hug
_uck
duck
_ub
rub
_un
fun
_us
bus
_ud
bud
_umb
thumb
_um
drum
_ug
rug