d
d
d
a
d
d
b
a
a
b
a
a
b
b
b
b
b
b
d
a
d
d
c
d
d
e
a
d
a
b
d
d
d
d
d
d
c
d
d
a
d
e
e
b
b
b
a
d
b
b
d
c
c
d
a
d
d
b
a
b
a
d
d
d
b
a
a
b
d
a
d
d
a
a
b
b
a
a
b
a