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