// Judges with GCC >= 12 only needs Ofast
// #pragma GCC optimize("O3,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
// MLE optimization
// #pragma GCC optimize("conserve-stack")
// Old judges
// #pragma GCC target("sse4.2,popcnt,lzcnt,abm,mmx,fma,bmi,bmi2")
// New judges. Test with assert(__builtin_cpu_supports("avx2"));
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
// Atcoder
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma")
#include<bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
uniform_real_distribution<> pp(0.0,1.0);
#define int long long
#define ld long double
#define pii pair<int,int>
#define piii pair<int,pii>
#define fi first
#define se second
const int inf=1e18;
const int mod=998244353;
const int mod2=1e9+7;
const int maxn=105;
const int maxq=1000005;
const int maxl=20;
const int maxa=1000005;
int power(int a,int n){
int res=1;
while(n){
if(n&1) res=res*a%mod;
a=a*a%mod;n>>=1;
}
return res;
}
int n,m,k,q,dist[2][maxn][maxn],len[maxn][maxn],ans[maxq];
void solve(){
cin >> n >> m;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++) len[i][j]=dist[0][i][j]=(i==j?0:inf);
}
for(int i=1;i<=m;i++){
int u,v,w;cin >> u >> v >> w;
len[u][v]=min(len[u][v],w);
}
cin >> k >> q;k=min(k,n-1);
int t=0;
for(int i=1;i<=k;i++){
t^=1;
for(int u=1;u<=n;u++){
for(int v=1;v<=n;v++) dist[t][u][v]=dist[t^1][u][v];
}
for(int u=1;u<=n;u++){
for(int v=1;v<=n;v++){
if(dist[t^1][u][v]==inf) continue;
for(int p=1;p<=n;p++) dist[t][u][p]=min(dist[t][u][p],dist[t^1][u][v]+len[v][p]);
}
}
}
for(int i=1;i<=q;i++){
int u,v;cin >> u >> v;
cout << (dist[t][u][v]==inf?-1:dist[t][u][v]) << '\n';
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
int test=1;//cin >> test;
while(test--) solve();
}
