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