B
B
A
A
B
B
A
A
D
D
C
C
A
A
A
D
D
A
A
C
C
B
B
D
D
A
A
C
C
A
A
A
A
D
D
A
A
C
C
B
B
B
B
A
A
C
C
B
B
C
C
C
A
A
D
D
A
A
B
B
D
D
D
D
C
C
B
B
C
C
C
C
B
B
D
D
B
B
D
D
D
D
B
B
A
A
A
A
C
C
D
D
B
B
C
C
C
C
D
D
C
C
D
D
B
B
D
C
C
A
A
D
D
D
D
B
B
C
C
D
D
D
D
A
A
D
D
B
B
B
B
D
C
A
A
B
B
C
C
C
C
C
C
B
B
A
A
A
A
B
B
A
B
B