#include <bits/stdc++.h>

using namespace std;

// #define int long long
// #define x first
// #define y second
#define File(a) freopen(a".in", "r", stdin), freopen(a".out", "w", stdout)

inline void debug() { cerr << '\n'; }
template<typename Type, typename... Other>
inline void debug(const Type& x, const Other&... y) { cerr << x << ' '; debug(y...); }
#define DEBUG(a...) cerr << "[" << #a << "] = ", debug(a);

typedef long long LL;
typedef pair<int, int> PII;

const int N = 310;
const int INF = 0x3f3f3f3f;

template<typename Type>
inline void read(Type &res)
{
    res = 0;
    int ch = getchar(), flag = 0;
    while (!isdigit(ch)) flag |= ch == '-', ch = getchar();
    while (isdigit(ch)) res = (res << 3) + (res << 1) + (ch ^ 48), ch = getchar();
    res = flag ? -res : res;
}
template<typename Type, typename... Other>
inline void read(Type &res, Other&... y) { read(res), read(y...); }

int n, m, q, C;
int dist[N][N], times[N][N];

signed main()
{
    memset(dist, 0x3f, sizeof dist);
    read(n, m, C);
    while (m --)
    {
        int a, b, c; read(a, b, c);
        dist[a][b] = dist[b][a] = c;
    }
    for (int ver = 1; ver <= n; ver ++) dist[ver][ver] = 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]);
    for (int ver = 1; ver <= n; ver ++)
        for (int to = 1; to <= n; to ++)
        {
            if (dist[ver][to] > C) times[ver][to] = INF;
            else times[ver][to] = 1;
            if (ver == to) times[ver][to] = 0;
        }
    for (int k = 1; k <= n; k ++)
        for (int ver = 1; ver <= n; ver ++)
            for (int to = 1; to <= n; to ++)
                times[ver][to] = min(times[ver][to], times[ver][k] + times[k][to]);

    read(q);
    while (q --)
    {
        int a, b; read(a, b);
        cout << (times[a][b] == INF ? -1 : times[a][b] - 1) << '\n';
    }

    return 0;
}