1:  8 6 4
2:  9 7 5 3
3:  5 2
4:  10 6 1
5:  6 3 2
6:  10 8 5 4 1
7:  9 2
8:  6 1
9:  7 2
10:  6 4
parent articulation vertex: 2 
parent articulation vertex: 5 
parent articulation vertex: 6 via bridge
non-leaf articulation vertex: 5 
