1 1
f f
g g
a
a a
0 0 1 a b b b a
b b
a
b
c
d
e
f
g
h
i
j
0 0 1 1 0 0 0 0
j j
j
i i
i
h h
h
g g
g
f f
f
e e
e
d d
d
c c
c
b b
b
a a
a