I

I-

III

II

III-II

2

1

2-1

4

3

4-3

6

5

6-5

8

7

8-7

10

9

10-9

12

11

12-11

14

13

14-13

16

15

16-15

18

17

18-17

20

19

20-19

22

21

22-21

24

23

24-23

26

25

26-25

27

27