#include "bits/stdc++.h"
using namespace std;
#define pb push_back
#define endl "\n"
#define int long long
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
void solve(){
int n,m;
cin >> n >> m;
int dp[n+5][n+5][n+5];
int matr[n+5][n+5];
memset(dp,-1,sizeof(dp));
memset(matr,-1,sizeof(matr));
for(int i=1;i<=m;i++){
int a,b,c;
cin >> a >> b >> c;
if(matr[a][b]==-1) matr[a][b]=c;
else matr[a][b]=min(matr[a][b],c);
}
for(int i=1;i<=n;i++) matr[i][i]=0;
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
dp[i][j][1]=matr[i][j];
int k,q;
cin >> k >> q;
for(int a=2;a<=min(k,n);a++){
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
for(int u=1;u<=n;u++){
if(dp[i][u][a-1] == -1 || matr[u][j] == -1) continue;
if(dp[i][j][a]==-1) dp[i][j][a]=dp[i][u][a-1]+matr[u][j];
else dp[i][j][a]=min(dp[i][j][a],dp[i][u][a-1]+matr[u][j]);
}
}
}
}
while(q--){
int a,b;
cin >> a >> b;
int ans=-1;
for(int i=1;i<=min(k,n);i++){
if(dp[a][b][i]==-1) continue;
if(ans==-1) ans=dp[a][b][i];
else ans=min(ans,dp[a][b][i]);
}
cout << ans << endl;
}
}
int32_t main(){
cin.tie(0); ios::sync_with_stdio(0);
int t=1;//cin >> t;
while(t--) solve();
return 0;
}
