输入
数据少于10组，保证只有一个源点和汇点。输入一个顶点数n(2<=n<=10000)，边数m(1<=m <=50000)。接下来m行输入边，分别是边起点sv，边终点ev，边权值w（1<=sv,ev<=n,sv != ev,1<=w <=20)。数据保证图连通。
输出
关键路径的权值和，并且从源点输出关键路径上的路径（如果有多条，请输出字典序最小的）
输入样例
9 11
1 2 6
1 3 4
1 4 5
2 5 1
3 5 1
4 6 2
5 7 9
5 8 7
6 8 4
8 9 4
7 9 2
输出样例
18
1 2
2 5
5 7
7 9(input
The data is less than 10 groups, ensuring only one source and a sink. Input a number of vertices n (2<=n<=10000), the number of edges m (1<=m <=50000). Next, the M line is the input side, which is the edge starting point SV, the edge point EV, and the edge weight W (1<=sv, ev<=n, SV! = EV, 1<=w <=20). The data ensures that the graph is connected.
output
The weight of the key path and the path of the key path from the source point (if there are many, please output the smallest dictionary order)
sample input
9 1 1
1 2 6
1 3 4
1 4 5
2 5 1
3 5 1
4 6 2
5 7 9
5 8 7
6 8 4
8 9 4
7 9 2

sample output
18
12
25
57
79)