// 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;
}
vector<pii> query[maxn],edge[maxn];
int n,m,k,q,dist[maxn][maxn],ans[maxq];
void dijisktra(int s){
for(int i=1;i<=n;i++){
for(int j=0;j<=k;j++) dist[i][j]=inf;
}
priority_queue<piii,vector<piii>,greater<piii>> pq;
dist[s][0]=0;pq.push({0,{s,0}});
while(!pq.empty()){
int u=pq.top().se.fi,num=pq.top().se.se,d=pq.top().fi;pq.pop();
if(dist[u][num]!=d) continue;
for(pii v:edge[u]){
if(d+v.second<dist[v.first][num+1]){
dist[v.first][num+1]=d+v.second;
if(num+1<k) pq.push({d+v.second,{v.first,num+1}});
}
}
}
for(pii v:query[s]){
int Min=inf;
for(int j=0;j<=k;j++) Min=min(Min,dist[v.first][j]);
ans[v.second]=(Min==inf?-1:Min);
}
}
void solve(){
cin >> n >> m;
for(int i=1;i<=m;i++){
int u,v,w;cin >> u >> v >> w;
edge[u].push_back({v,w});
}
cin >> k >> q;k=min(k,n-1);
for(int i=1;i<=q;i++){
int u,v;cin >> u >> v;
query[u].push_back({v,i});
}
for(int i=1;i<=n;i++){
if(!query[i].empty()) dijisktra(i);
}
for(int i=1;i<=q;i++) cout << ans[i] << '\n';
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
int test=1;//cin >> test;
while(test--) solve();
}
