Input:
6
0 0
1 1
1 0
2 1
2 0
3 0
7
1 2 12
1 3 2
2 4 10
3 4 10
3 5 10
4 6 1
5 6 13

Output:
11
1 2 9
1 3 2
2 4 9
4 3 8
3 5 10
4 6 1
5 6 10