Problem Statement
There are $N$ towns numbered $1$ to $N$ and $M$ roads. The $i$-th road connects Town $A_i$ and Town $B_i$ bidirectionally and has a length of $C_i$.
Takahashi will travel between these towns by car, passing through these roads. The fuel tank of his car can contain at most $L$ liters of fuel, and one liter of fuel is consumed for each unit distance traveled. When visiting a town while traveling, he can full the tank (or choose not to do so). Travel that results in the tank becoming empty halfway on the road cannot be done.
Process the following $Q$ queries:
- The tank is now full. Find the minimum number of times he needs to full his tank while traveling from Town
$s_i$to Town$t_i$. If Town$t_i$is unreachable, print$-1$.
Constraints
- All values in input are integers.
$2 \leq N \leq 300$$0 \leq M \leq \frac{N(N-1)}{2}$$1 \leq L \leq 10^9$$1 \leq A_i, B_i \leq N$$A_i \neq B_i$$\left(A_i, B_i\right) \neq \left(A_j, B_j\right)$(if$i \neq j$)$\left(A_i, B_i\right) \neq \left(B_j, A_j\right)$(if$i \neq j$)$1 \leq C_i \leq 10^9$$1 \leq Q \leq N\left(N-1\right)$$1 \leq s_i, t_i \leq N$$s_i \neq t_i$$\left(s_i, t_i\right) \neq \left(s_j, t_j\right)$(if$i \neq j$)
Input
Input is given from Standard Input in the following format:
N M L
A_1 B_1 C_1
:
A_M B_M C_M
Q
s_1 t_1
:
s_Q t_Q
Output
Print $Q$ lines.
The $i$-th line should contain the minimum number of times the tank needs to be fulled while traveling from Town $s_i$ to Town $t_i$. If Town $t_i$ is unreachable, the line should contain $-1$ instead.
样例
3 2 5
1 2 3
2 3 3
2
3 2
1 3
0
1
4 0 1
1
2 1
-1
5 4 4
1 2 2
2 3 2
3 4 3
4 5 2
20
2 1
3 1
4 1
5 1
1 2
3 2
4 2
5 2
1 3
2 3
4 3
5 3
1 4
2 4
3 4
5 4
1 5
2 5
3 5
4 5
0
0
1
2
0
0
1
2
0
0
0
1
1
1
0
0
2
2
1
0
题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。