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