1
A
B
2
A
B
3
A
B
4
A
B
5
A
B
6
A
B
7
A
B
8
A
B
9
A
B
10
A
B
11
A
B
12
A
B
13
A
B
14
A
B
15
A
B
16
A
B
17
A
B
18
A
B
19
A
B
20
A
B