B

A

C

A

C

A

B

D

B

D

B

B

C

C

A

C

D

A

D

B

D

A

A

A

C

C

D

A

B

C

C

A

C

C

A

A

A

A

D

B

D

C

A

A

A

C

B

A

B

B

B

D