#959. Shortest path (Dijkstra)
You get n vertices and m undirected weighted edges. Find the length of the shortest path from vertex 1 to vertex n. If n cannot be reached, print -1.
### Input
n m, then m lines `u v w`.
### Output
A number.
Examples
Input
5 4 1 5 11 2 4 8 5 2 10 2 5 12
Output
11
Input
2 4 2 2 12 2 1 14 1 1 2 1 1 9
Output
14
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.