#include <bits/stdc++.h>
#define ll long long
#define pll pair<ll,ll>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
const ll maxn = 71*71+10;
const ll add = 1e5;
ll n, m;
vector<pair<ll,ll>> T[80];
ll dis[71][71][80];
bool chk[71][71][80];
vector<pair<pll,ll>> road;
void solve_this(ll v)
{
//cout << v << "\n";
for(int i = 1; i<= n; i++)
{
//if(v==70) cout << i << " ";
for(int j = 0; j<= 71; j++)
{
dis[v][i][j] = LLONG_MAX;
//if(v==70&&i==69) cout << dis[v][i][j] << "-\n";
chk[v][i][j] = 0;
}
}
dis[v][v][0] = 0;
chk[v][v][0] = 1;
//cout << dis[70][69][71] << " " << v << "-\n";
ll tong = 0;
for(int j = 1; j<= 71; j++)
{
for(int i = 1; i<= n; i++)
{
//cout << i << " " << j << "\n";
if(!chk[v][i][j-1]) continue;
for(auto u: T[i])
{
tong++;
chk[v][u.fi][j] = 1;
dis[v][u.fi][j] = min(dis[v][u.fi][j], dis[v][i][j-1]+u.se);
//if(v==70&&dis[v][i][j]==0&&i!=v)
//{
//cout << u.se << "\n";
//cout << u.fi << " " << dis[v][i][j] << " " << j << " " << i << "\n";
//}
}
}
}
//cout << dis[70][69][71] << " " << v << "\n";
}
void solve()
{
cin >> n >> m;
for(int i = 0; i< m; i++)
{
ll a, b, c; cin >> a >> b >> c;
road.push_back(mp(mp(a, b), c));
}
sort(road.begin(), road.end());
for(int i = 1; i<= n; i++)
{
T[i].push_back(mp(i, 0));
}
for(int i = 0; i< m; i++)
{
if(i==0)
{
//cout << road[i].se<< "\n";
T[road[i].fi.fi].push_back(mp(road[i].fi.se,road[i].se));
continue;
}
if(road[i].fi==road[i-1].fi) continue;
else
{
//cout << road[i].se<< "\n";
T[road[i].fi.fi].push_back(mp(road[i].fi.se,road[i].se));
}
}
for(int i = 1; i <= n; i++) solve_this(i);
ll k, q;
cin >> k >> q;
k = min(k, (ll)71);
for(int i = 0; i< q; i++)
{
ll a, b; cin >> a >> b;
//if(a==1) cout << a << " " << b << " " << dis[a][b][k] << "\n"
//if(dis[a][b][k]==0) cout << a << " " << b << "\n";
if(dis[a][b][k]==LLONG_MAX) cout << -1;
else cout << dis[a][b][k];
cout << "\n";
}
}
int main()
{
ios_base::sync_with_stdio(NULL) ; cin.tie(nullptr) ; cout.tie(nullptr);
//freopen("B.inp","r",stdin);
ll test_case = 1;
while(test_case--)
{
solve();
}
}
