#include "bits/stdc++.h"
#define fast ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ll long long
#define pb push_back
#define in insert
#define F first
#define S second
#define vll vector<ll>
#define all(v) v.begin(), v.end()
#define rep(a, b, c) for (int(a) = (b); (a) < (c); (a)++) // i, 0, n
#define endl '\n'
#define pii pair<ll,ll>
#define yes cout << "Yes" << endl;
#define no cout << "No" << endl;
using namespace std;
const ll INF = 1e18, mod = 1e9 + 7, N = 1e5 + 5;
ll gcd(ll a, ll b) {
return b == 0 ? a : gcd(b, a % b);
}
ll lcm(ll a, ll b) {
return (a / gcd(a, b)) * b;
}
ll modpow(ll a, ll b) {
ll ans = 1;
while(b > 0) {
if(b % 2 == 1) {
ans *= a;
ans %= mod;
}
a *= a;
a %= mod;
b >>= 1;
}
return ans % mod;
}
ll inv(ll a) {
return modpow(a, mod-2) % mod;
}
ll dis[75][75], fly[75][75][75];
void solve(){
ll n,m;
cin >> n >> m;
for(int i = 1; i <= n; i++){
for(int j= 1; j <= n; j++){
for(int h = 1; h <= n; h++){
fly[j][h][i] = INF;
}
}
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
if(i == j){
dis[i][j] = 0;
}
else{
dis[i][j] = INF;
}
fly[i][j][0] = dis[i][j];
}
}
ll x,y,z;
for(int i = 1; i <= m; i++){
cin >> x >>y>>z;
dis[x][y] = min(dis[x][y], z);
fly[x][y][1] = dis[x][y];
}
// cout << fly[1][4][2] << endl;
for(int i = 1; i < n; i++){
for(int f = 1; f <= n; f++){
for(int j = 1; j <= n; j++){
for(int h = 1; h <= n; h++){//j = 1, h = 4, i = 2, 1,2,1 + 2 4 j , f i - 1 + f h
fly[j][h][i] = min(fly[j][h][i], fly[j][f][i - 1] + dis[f][h]);
}
}
}
}
ll k,q;
cin >> k >> q;
ll u, p;
while(q--){
cin >> u >> p;
if(u == p){
cout << 0 << endl;
continue;
}
if(fly[u][p][k] == INF || fly[u][p][k] == 0){
cout << -1 << endl;
continue;
}
cout << fly[u][p][k] << endl;
}
}
int main() {
fast;
ll t = 1;
// cin >> t;
while(t--){
solve();
}
}
