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F. K-th Path
time limit per test
2.5 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

You are given a connected undirected weighted graph consisting of $$$n$$$ vertices and $$$m$$$ edges.

You need to print the $$$k$$$-th smallest shortest path in this graph (paths from the vertex to itself are not counted, paths from $$$i$$$ to $$$j$$$ and from $$$j$$$ to $$$i$$$ are counted as one).

More formally, if $$$d$$$ is the matrix of shortest paths, where $$$d_{i, j}$$$ is the length of the shortest path between vertices $$$i$$$ and $$$j$$$ ($$$1 \le i < j \le n$$$), then you need to print the $$$k$$$-th element in the sorted array consisting of all $$$d_{i, j}$$$, where $$$1 \le i < j \le n$$$.

Input

The first line of the input contains three integers $$$n, m$$$ and $$$k$$$ ($$$2 \le n \le 2 \cdot 10^5$$$, $$$n - 1 \le m \le \min\Big(\frac{n(n-1)}{2}, 2 \cdot 10^5\Big)$$$, $$$1 \le k \le \min\Big(\frac{n(n-1)}{2}, 400\Big)$$$ — the number of vertices in the graph, the number of edges in the graph and the value of $$$k$$$, correspondingly.

Then $$$m$$$ lines follow, each containing three integers $$$x$$$, $$$y$$$ and $$$w$$$ ($$$1 \le x, y \le n$$$, $$$1 \le w \le 10^9$$$, $$$x \ne y$$$) denoting an edge between vertices $$$x$$$ and $$$y$$$ of weight $$$w$$$.

It is guaranteed that the given graph is connected (there is a path between any pair of vertices), there are no self-loops (edges connecting the vertex with itself) and multiple edges (for each pair of vertices $$$x$$$ and $$$y$$$, there is at most one edge between this pair of vertices in the graph).

Output

Print one integer — the length of the $$$k$$$-th smallest shortest path in the given graph (paths from the vertex to itself are not counted, paths from $$$i$$$ to $$$j$$$ and from $$$j$$$ to $$$i$$$ are counted as one).

Examples
Input
6 10 5
2 5 1
5 3 9
6 2 2
1 3 1
5 1 8
6 5 10
1 6 5
6 4 6
3 6 2
3 4 5
Output
3
Input
7 15 18
2 6 3
5 7 4
6 5 4
3 6 9
6 7 7
1 6 4
7 1 6
7 2 1
4 3 2
3 2 8
5 3 6
2 5 5
3 7 9
4 1 8
2 1 1
Output
9