A
C
C
B
D
B
A
C
A
D
A
A
D
A
A
A
B
A
B
C
C
A
D
B
D
A
B
A
C
A
C
A
B
A
B
D
A
B
C
A
C
B
A
B
C
D
A
B
A
A
C
D
A
A
D
A
B
C
B
A
D
A
B
A
D
A
C
A
C
D
A
C
B
D
A
B
C
B
C
A
D
C
A
C
A
A
C
A
BD
A
B
A
D
C
B
AB
D
B
B
A