3

6

2a

b

3

4 a

5

6 a

8 a

9

10 b

1

2 a

b

3 a

b

4 b

6

8

1 a

b

2 a

3 b

1 a

2 a

1 a

2 a

6

7 a

1b

c

2

3

6 b

7 a

2

3 a

5

b

7 a

8 a

c

9 b

3