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