2 a 2
2 a 2
2 a 3
2 a 3
2 a 4
2 a 4
2 a 5
2 a 5
2 a 6
2 a 6
3 a 2
3 a 2
3 a 3
3 a 3
3 a 4
3 a 4
3 a 5
3 a 5