Given a directed graph, find the length of the shortest path from to .
, the number of vertices.
, the number of edges. lines, each with three integers , , indicating a directed edge from to of length .
Bonus: one case will have edges with negative lengths.
A shortest path will always exist.
The length of the shortest path from vertex to vertex .
3 3 1 2 1 2 3 2 1 3 5
Take the path .