case 1 failed: flow conservation failed at node 2: in=6, out=76
input:
12 17
6 12 78
2 5 34
7 9 44
9 12 80
2 8 42
6 10 90
8 10 46
1 7 72
3 9 24
7 8 100
8 11 34
5 9 28
4 7 42
5 7 58
1 2 6
4 11 44
3 12 34

output:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
exit status 1