A

B

C

D

1

B

B

A

A

2

C

D

C

D

3

C

A

A

C

4

B

C

C

D

5

D

B

A

D

6

A

C

C

A

7

D

A

B

B

8

A

C

D

B

9

C

A

B

C

10

A

D

D

A

11

B

D

A

C

12

A

A

C

A

13

C

A

B

A

14

D

C

A

C

15

A

B

D

B

16

C

A

A

C

17

A

C

C

D

18

D

D

A

D

19

C

A

C

A

20

A

C

D

B