#include <bits/stdc++.h>
using namespace std;

#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

#define ll long long
#define ld long double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define FOR(i,l,r) for(int i=(l);i<=(r);i++)
#define ROF(i,r,l) for(int i=(r);i>=(l);i--)
int inf=1000000007;
ll infl=1000000000000000007;
ll mod=1000000007;

const int N=17;

ll d[N][N][N];
bool odw[N][N][N];
vector<pair<int,ll>>G[N];

int x[N];

signed main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,m,q,L;
	cin>>n>>m>>q>>L;
	FOR(i,1,m)
	{
		int a,b,c;
		cin>>a>>b>>c;
		G[a].pb({b,c});
		G[b].pb({a,c});
	}
	FOR(i,1,L) cin>>x[i];
	while(q--)
	{
		int p;
		cin>>p>>x[p];
		FOR(i,1,L) 
		{
			FOR(j,1,n)
			{
				FOR(l,1,n)
				{
					d[i][j][l]=infl;
					odw[i][j][l]=0;
				}
			}
		}
		priority_queue<pair<ll,vector<int>>>Q;
		Q.push({0,{1,x[1],x[1]}});
		d[1][x[1]][x[1]]=0;
		ll ans=infl;
		while(sz(Q)>0)
		{
			int i=Q.top().nd[0],v=Q.top().nd[1],o=Q.top().nd[2];
			Q.pop();
			if(odw[i][v][o]) continue;
			debug(i,v,o,d[i][v][o]);
			odw[i][v][o]=1;
			if(i==L) 
			{
				ans=d[i][v][o];
				break;
			}
			if(v==x[i+1]&&d[i][v][o]<d[i+1][v][o])
			{
				d[i+1][v][o]=d[i][v][o];
				Q.push({-d[i+1][v][o],{i+1,v,o}});
			}
			for(auto [u,c]:G[v])
			{
				if(u==o) continue;
				if(d[i][v][o]+c<d[i][u][v])
				{
					d[i][u][v]=d[i][v][o]+c;
					Q.push({-d[i][u][v],{i,u,v}});
				}
			}
		}
		if(ans==infl) cout<<-1<<endl;
		else cout<<ans<<endl;
	}
	
	return 0;
}