f
b
b
b
c
b
d
a
b
c
d
e
f
g
c
a
a
b
d
d
a
f
b
b
b
c
b
e
e
f
a
b
f
a
b
f
d
a
f
b
b
f
c
b
b
a
b
b
b
a
b
b
b
b
b
b
a
a
f
d
d
a
g
b
c
b
d
g
f
d
d
b
b
g
b
c
d
b
b
b