#include <bits/stdc++.h>
using namespace std;
#define Rep(i,n) for(int i=0;i<(int)(n);i++)
#define For(i,n1,n2) for(int i=(int)(n1);i<(int)(n2);i++)
#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define RREP(i,n) for(ll i=((ll)(n)-1);i>=0;i--)
#define FOR(i,n1,n2) for(ll i=(ll)(n1);i<(ll)(n2);i++)
#define RFOR(i,n1,n2) for(ll i=((ll)(n1)-1);i>=(ll)(n2);i--)
#define all(a)  (a).begin(),(a).end()
#define SORT(a) sort((a).begin(),(a).end())
#define oorret 0
#define oor(x) [&](){try{x;} catch(const out_of_range& oor){return oorret;} return x;}()
#define IOS cin.tie(0),ios::sync_with_stdio(false)
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
template<typename T1, typename T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return 1; }return 0; }
template<typename T1, typename T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return 1; }return 0; }
template<class Type>struct is_vector : std::false_type {};
template<class ValueType, class Alloc>struct is_vector<std::vector<ValueType, Alloc>> : std::true_type {};
template <typename T> inline ostream& operator << (ostream& out, const vector<T>& v) {
	if (v.empty())return out;
	constexpr bool is_vector_v = is_vector<T>::value;
	if (is_vector_v)for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? "\n" : "");
	else for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? " " : "");
	return out;
}
inline void put() {}
template<class T> inline void put(const T& first) { std::cout << first << "\n"; }
template<class T, class... N> inline void put(const T& first, const N& ... rest) { std::cout << first << " "; put(rest...); }
inline void putn() {}
template<class T, class... N> inline void putn(const T& first, const N& ... rest) { std::cout << first << "\n"; putn(rest...); }

template<typename T>
struct edge {
	int to;
	T cost;
	edge(int t, T c) {
		to = t;
		cost = c;
	}
};

/*ll l;
struct vcost {
	ll sup, c;
	vcost(ll s, ll c){
		this->sup = s;
		this->c = c;
		if (c > l) {
			sup++;
			c = 0;
		}
	}
	bool comp(vcost v) {
		if (v.sup == this->sup) {
			return v.c > this->c;
		} else {
			return v.sup > this->sup;
		}
	}
};*/

ll lim = 1e13, l;
ll calc(ll t, ll s) {
	ll t1 = t % lim;
	ll t2 = t / lim;
	if (t1 + s > l) {
		t2++;
		t1 = s;
	} else {
		t1 += s;
	}
	ll res = t2 * lim + t1;
	return res;
}

template<typename T>
void dijkstra(int s, vector<vector<edge<T>>>& path, vector<T>& d) {
	using pi = pair<T, int>;
	priority_queue<pi, vector<pi>, greater<pi>> q;
	q.push(P(0, s));
	d[s] = 0;
	while (!q.empty()) {
		P p = q.top();
		q.pop();
		int v = p.second;
		if (d[v] < p.first)continue;
		REP(i, path[v].size()) {
			edge<T> e = path[v][i];
			ll temp = calc(d[v], e.cost);
			if (d[e.to] > temp) {
				d[e.to] = temp;
				q.push(P(d[e.to], e.to));
			}
		}
	}
	return;
}

int main() {
	IOS;
	ll n, m;
	cin >> n >> m >> l;
	vector<ll> a(m), b(m), c(m);
	vector<vector<edge<ll>>> path(n);
	REP(i, m) {
		cin >> a[i] >> b[i] >> c[i];
		a[i]--;
		b[i]--;
		if (c[i] <= l) {
			path[a[i]].push_back(edge<ll>(b[i], c[i]));
			path[b[i]].push_back(edge<ll>(a[i], c[i]));
		}
	}
	vector<vector<ll>> d(n, vector<ll>(n, LLONG_MAX/2));
	REP(i, n) {
		dijkstra(i, path, d[i]);
	}
	int q;
	cin >> q;
	vector<int> s(q), t(q);
	REP(i, q) {
		cin >> s[i] >> t[i];
		s[i]--;
		t[i]--;
	}
	REP(i, q) {
		if (d[s[i]][t[i]] == LLONG_MAX / 2) {
			put(-1);
		} else {
			put(d[s[i]][t[i]] / lim);
		}
	}
	return 0;
}


Measured memory_bytes: 5508