#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1000000000000000000LL;
pair<int,pair<int,int> > edgel[4005];
vector<int> inedge[2005];
vector<int> outedge[2005];
int distm[4005][4005];
pair<int,int> thing1[2005][4005]; //node, edge
pair<int,int> thing2[2005][4005];
int n,m;
int T,L;
int arr[100005];
void handle(int &dist1, int &e1, int &dist2, int &e2, pair<int,int> opt){
if (e1==opt.second){
if (opt.first<=dist1){
dist1 = opt.first;
}
}
else if (e2==opt.second){
if (opt.first<=dist2){
dist2 = opt.first;
}
}
else if (opt.first<=dist1){
dist2 = dist1;
e2 = e1;
dist1 = opt.first;
e1 = opt.second;
}
else if (opt.first<=dist2){
dist2 = opt.first;
e2 = opt.second;
}
if (dist1>dist2){
swap(dist1,dist2);
swap(e1,e2);
}
}
main(){
scanf("%lld%lld",&n,&m);
scanf("%lld%lld",&T,&L);
for (int x = 0; x<m; x++){
int a,b,c;
scanf("%lld%lld%lld",&a,&b,&c);
edgel[2*x] = {c,{a,b}};
edgel[2*x+1] = {c,{b,a}};
inedge[a].push_back(2*x+1);
outedge[a].push_back(2*x);
inedge[b].push_back(2*x);
outedge[b].push_back(2*x+1);
}
priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > > pq;
for (int x = 0; x<2*m; x++){
for (int y = 0; y<2*m; y++){
distm[x][y] = INF;
}
distm[x][x] = 0;
pq.push({0,x});
while (!pq.empty()){
int u = pq.top().second;
int d = pq.top().first;
pq.pop();
if (d>distm[x][u]) continue;
for (auto y : outedge[edgel[u].second.second]){
if ((y^1)==u) continue;
if (d+edgel[y].first<distm[x][y]){
distm[x][y] = d+edgel[y].first;
pq.push({distm[x][y],y});
}
}
}
}
for (int x = 0; x<=2*m; x++){
for (int y = 1; y<=m; y++){
thing1[y][x] = {INF,-1};
thing2[y][x] = {INF,-1};
}
}
for (int x = 0; x<2*m; x++){
for (int y = 0; y<2*m; y++){
if (distm[x][y]<INF){
pair<int,int> nw = {distm[x][y],y};
if (nw<=thing1[edgel[y].second.second][x]){
thing2[edgel[y].second.second][x] = thing1[edgel[y].second.second][x];
thing1[edgel[y].second.second][x] = nw;
}
else if (nw<=thing2[edgel[y].second.second][x]){
thing2[edgel[y].second.second][x] = nw;
}
}
}
}
for (int x = 0; x<L; x++){
scanf("%lld",&arr[x+1]);
}
for (int i = 0; i<T; i++){
int a,b;
scanf("%lld%lld",&a,&b);
arr[a] = b;
int dist1 = INF;
int e1 = -1;
int dist2 = INF;
int e2 = -1;
for (auto x : outedge[arr[1]]){
auto t1 = thing1[arr[2]][x];
t1.first += edgel[x].first;
if (e1==t1.second){
if (t1.first<=dist1){
dist1 = t1.first;
}
}
else if (e2==t1.second){
if (t1.first<=dist2){
dist2 = t1.first;
}
}
else if (t1.first<=dist1){
dist2 = dist1;
e2 = e1;
dist1 = t1.first;
e1 = t1.second;
}
else if (t1.first<=dist2){
dist2 = t1.first;
e2 = t1.second;
}
if (dist1>dist2){
swap(dist1,dist2);
swap(e1,e2);
}
auto t2 = thing2[arr[2]][x];
t2.first += edgel[x].first;
if (e1==t2.second){
if (t2.first<=dist1){
dist1 = t2.first;
}
}
else if (e2==t2.second){
if (t2.first<=dist2){
dist2 = t2.first;
}
}
else if (t2.first<=dist1){
dist2 = dist1;
e2 = e1;
dist1 = t2.first;
e1 = t2.second;
}
else if (t2.first<=dist2){
dist2 = t2.first;
e2 = t2.second;
}
if (dist1>dist2){
swap(dist1,dist2);
swap(e1,e2);
}
}
if (dist1==INF){
printf("-1\n");
continue;
}
for (int x = 3; x<=L; x++){
//printf("vals are %lld %lld %lld %lld\n",dist1,e1,dist2,e2);
int ndist1 = INF;
int ne1 = -1;
int ndist2 = INF;
int ne2 = -1;
auto t1 = thing1[arr[x]][e1];
t1.first += dist1;
handle(ndist1,ne1,ndist2,ne2,t1);
auto t2 = thing2[arr[x]][e1];
t2.first += dist1;
handle(ndist1,ne1,ndist2,ne2,t2);
auto t3 = thing1[arr[x]][e2];
t3.first += dist2;
handle(ndist1,ne1,ndist2,ne2,t3);
auto t4 = thing2[arr[x]][e2];
t4.first += dist2;
handle(ndist1,ne1,ndist2,ne2,t4);
dist1 = ndist1;
dist2 = ndist2;
e1 = ne1;
e2 = ne2;
if (dist1==INF){
printf("-1\n");
break;
}
}
if (dist1==INF) continue;
printf("%lld\n",dist1);
}
}
