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