Problem7673--[CSES Problem Set] Graph Paths II

7673: [CSES Problem Set] Graph Paths II

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Time Limit : 1.000 sec  Memory Limit : 256 MiB

Description

Consider a directed graph that has $n$ nodes and $m$ edges. 
Your task is to count the number of paths from node $1$ to node $n$ with exactly $k$ edges.

Input

The first input line contains three integers $n, m, k$: the number of nodes and edges, and the length of the path. The nodes are numbered $1,2,\dots,n$.
Then, there are $m$ lines describing the edges. Each line contains three integers $a,b,c$: there is an edge from node $a$ to node $b$ with weight $c$.

Output

Print the minimum path length. If there are no such paths, print $-1$.

Constraints

$1≤n≤100$
$1 \le m \le n(n-1)$
$1 \le k \le 10^9$
$1 \le a,b \le n$

Sample 1 Input

3 4 8
1 2 5
2 3 4
3 1 1
3 2 2

Sample 1 Output

27

HINT

相同题目:CSES 1724

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