#include<bits/stdc++.h>
#define fi first
#define se second
#define pitem item*
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<ll> vl;
const int N=100;
const int SS=1<<19;
const int INFi=2e9;
const ll INFl=1e13;
const ll mod2=998244353;
const ll mod=1e9+7;
const ll mod3=1000696969;
const ll p=70032301;
const ull p2=913;
const int L=20;
int t[N],odl[N][N],dp[N][N][N];
void solve(){
int n,m;
cin>>n>>m;
for(int i=1;i<=n;i++) for(int j=1;j<=n;j++) odl[i][j]=-1;
for(int a,b,c,i=1;i<=m;i++){
cin>>a>>b>>c;
if(odl[a][b]==-1) odl[a][b]=c;
else odl[a][b]=min(odl[a][b],c);
}
for(int i=1;i<=n;i++) odl[i][i]=0;
int k,q;
cin>>k>>q;
k=min(k,n);
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++) dp[i][j][0]=odl[i][j];
for(int il=1;il<=n;il++){
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
dp[i][j][il]=-1;
for(int sr=1;sr<=n;sr++){
if(dp[i][sr][il-1]!=-1 and odl[sr][j]!=-1){
if(dp[i][j][il]==-1) dp[i][j][il]=dp[i][sr][il-1]+odl[sr][j];
else dp[i][j][il]=min(dp[i][j][il],dp[i][sr][il-1]+odl[sr][j]);
}
}
}
}
}
while(q--){
int a,b;
cin>>a>>b;
cout<<dp[a][b][k-1]<<"\n";
}
}
int main(){
ios_base::sync_with_stdio(0),cin.tie(0);
int tt=1;
while(tt--) solve();
}
