10 13
0 1 2
1 2 1
2 4 1
0 3 1
3 4 5
4 5 -1
5 6 3
6 9 2
5 7 5
7 8 -4
8 6 1
8 9 2
6 2 -3
0 3

Directed Graph
                    -3
           +------------------------+
           |                        |
   2    1  v 1                3     |    2
 +--->1--->2---+        +---------->6---------->9
 |             v  -1    |           ^           ^
0+             4------>5+           |1          |
 |             ^        |           |           |
 +--->3--------+        +--->7----->8-----------+
  1        5              5    -4         2