// Problem: C. Travel
// Contest: undefined - NOIP2024训练赛 06
// URL: http://www.noi.ac/contest/1158/problem/2680
// Memory Limit: 1024 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define PII pair<int, int>

using namespace std;

const int N = 2e3 + 10, M = 1e6 + 10, mod = 1e9 + 7, INF = 0x3f3f3f3f3f3f3f3f;

int n, m, q, L, ans;
int s[N], dp[N], dist[N][N], val[N][N];

vector<PII> e[N];

inline void init()
{
	for(int i = 1; i <= n; i ++) dist[i][i] = 0;
	for(int k = 1; k <= n; k ++)
	{
		for(int i = 1; i <= n; i ++)
		{
			for(int j = 1; j <= n; j ++)
				dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
		}
	}
	memset(val, INF, sizeof val);
	for(int i = 1; i <= n; i ++) val[i][i] = 0;
	for(int i = 1; i <= n; i ++)
	{
		for (int j = 1; j <= n; j ++)
			if(dist[i][j] <= L) val[i][j] = val[j][j] = 1;
	}
	for(int k = 1; k <= n; k ++)
	{
		for(int i = 1; i <= n; i ++)
			for(int j = 1; j <= n; j ++)
				val[i][j] = min(val[i][j], val[i][k] + val[k][j]);
	}
}

signed main()
{
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cin >> n >> m >> L;
	memset(dist, INF, sizeof dist);
	for(int i = 1; i <= m; i ++)
	{
		int u, v, w; cin >> u >> v >> w;
		dist[u][v] = dist[v][u] = w;
		// e[u].push_back({v, w}), e[v].push_abck({u, w});
	}	
	init();
	cin >> q;
	while(q --)
	{
		int st, ed; cin >> st >> ed;
		// solve(st, ed);
		cout << (val[st][ed] == INF ? -1 : val[st][ed] - 1) << '\n';
	}
	return 0;
}