Problem:
Score : 500 points

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.

Sample Input 1

3 2 5
1 2 3
2 3 3
2
3 2
1 3

Sample Output 1

0
1

To travel from Town 3 to Town 2, we can use the second road to reach Town 2 without fueling the tank on the way.

To travel from Town 1 to Town 3, we can first use the first road to get to Town 2, full the tank, and use the second road to reach Town 3.

Sample Input 2

4 0 1
1
2 1

Sample Output 2

-1

There may be no road at all.

Sample Input 3

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

Sample Output 3

0
0
1
2
0
0
1
2
0
0
0
1
1
1
0
0
2
2
1
0

Solution in C++14 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define FAST std::ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define DECIMAL(n)  std::cout << std::fixed;std::cout << std::setprecision(n);
#define hell 1000000007
#define narak 998244353
#define PI 3.14159265358979323844
#define mp make_pair
#define eb emplace_back
#define pb push_back
#define fi first 
#define se second
#define ALL(v) v.begin(), v.end()
#define SORT(v) sort(ALL(v))  
#define REVERSE(v) reverse(ALL(v))
#define endl "\n"
#define maxc(v) *max_element(ALL(v))
#define minc(v) *min_element(ALL(v))
#define sqr(a) (a)*(a)
#define GCD(m,n) __gcd(m,n)
#define LCM(m,n) m*(n/GCD(m,n))
#define inputarr(a,n) for(int xxx=0;xxx<n;++xxx) cin>>a[xxx]
#define rep(i, n)    for(int i = 0; i < (n); ++i)
#define repA(i, a, n)  for(int i = a; i <= (n); ++i)
#define repD(i, a, n)  for(int i = a; i >= (n); --i)
#define trav(a, x) for(auto& a : x)
#define sz(a) (int)a.size()
#define sl(a) (int)a.length()
#define invect(data,n,commands) for(int xxx = 0;xxx<n;xxx++){int tmp;cin>>tmp;data.pb(tmp);commands}
#define inset(data,n,commands) for(int xxx = 0;xxx<n;xxx++){int tmp;cin>>tmp;data.insert(tmp);commands}
#define display(x) trav(a,x) cout<<a<<" ";cout<<endl
#define debug cerr<<"bhau"<<endl
#define between(n,a,b) (a<=n&&n<=b)
#define clamp(n,a,b) (((n)<(a))?(a):(((n)>(b))?(b):(n))) 

#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
    std::cerr << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
    const char* comma = strchr(names + 1, ',');std::cerr.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}

template<typename T, typename U> static inline void amin(T &x, U y) 
{ 
    if (y < x) 
        x = y; 
}
template<typename T, typename U> static inline void amax(T &x, U y) 
{ 
    if (x < y) 
        x = y; 
}

std::mt19937_64 rng(std::chrono::steady_clock::now().time_since_epoch().count());

#define ll long long
#define ld long double 
#define pii std::pair<int, int> 
#define pll std::pair<ll, ll>  
#define vi vector<int>  
#define vvi vector<vi > 
#define vii vector<pii >
#define point complex<ll>
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> 

/*----------------------Graph Moves----------------*/
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*------------------------------------------------*/

//primes for hashing 937,991,1013,1409,1741

std::ostream& operator<<(std::ostream& out,pii a)
{
    out<<a.fi<<" "<<a.se;
    return out;
}
std::ostream& operator<<(std::ostream& out,pll a)
{
    out<<a.fi<<" "<<a.se;
    return out;
}
std::istream& operator>>(std::istream& in,pii &a)
{
    in>>a.fi>>a.se;
    return in;
}
std::istream& operator>>(std::istream& in,pll &a)
{
    in>>a.fi>>a.se;
    return in;
}

using namespace std;
using namespace __gnu_pbds;
vector<pll> adj[303];
void meowmeow321()
{
    ll n,m,l;
    cin>>n>>m>>l;
    for (int i = 0; i < m; ++i)
    {
        ll a,b,c;
        cin>>a>>b>>c;
        if(c>l)continue;
        adj[a].eb(b,c);
        adj[b].eb(a,c);
    }
    pll dp[n+1][n+1];
    for (int s = 1; s <= n; ++s)
    {
        multiset<pair<pll,int>> wid;
        fill(dp[s],dp[s]+n+1,mp((ll)hell,0ll));        
        wid.insert({mp(0,-l),s});
        // dp[s][s]={0,-l};
        ll tt=0;
        while(sz(wid)){
            assert(sz(wid)<=2*m+1);
            assert(tt<=n);
            pll w=wid.begin()->fi;
            int id=wid.begin()->se;
            wid.erase(wid.begin());
            if(dp[s][id]==mp((ll)hell,0ll)){
                dp[s][id]=w;
                tt++;
                for(auto u:adj[id]){
                    if(dp[s][u.fi]==mp((ll)hell,0ll))
                    if(-w.se >=u.se)
                        wid.insert({mp(w.fi,w.se + u.se),u.fi});
                    else wid.insert({mp(w.fi+1,-l+u.se),u.fi});
                }
            }
        }
    }
    int q;
    cin>>q;
    for (int i = 0; i < q; ++i)
    {
        int a,b;
        cin>>a>>b;
        cout<<(dp[a][b].fi==hell?-1:dp[a][b].fi)<<endl;
    }
}
int main()
{
    FAST;
    int testcases=1;
    //cin>>testcases;
    for(int i=0;i<testcases;++i)
    {
        meowmeow321();
    }
    return 0;
}