4
3 2 1 0
1 2
2 0
4 6 1 3
0 1
0 2
0 2
0 3
1 3
2 3
5 6 2 3
0 1
1 2
2 3
3 1
1 4
4 0
5 7 2 3
0 1
1 2
2 3
3 1
1 4
4 0
0 2