// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
#define int long long
#define endl "\n"
#define fi first
#define se second
const int M=1e9+7;
const int inf = 1e14;
const int LOG=17;
const int N=1e5+5;
int n , m , c , w , k , t=1 , q=1 , x , y , z , l , r;
vector<pair<int,int>>a[N];
map<pair<int,int>,int>in;
map<int,pair<int,int>>it;
int sh[N];
int dp[LOG][N];
int di[N];
int vi[N];
int av[N];
int p[LOG][N];
int li[LOG][N];
void makest(){
for (int j=1;j<LOG;j++){
for (int i=1;i<=n;i++){
p[j][i]=p[j-1][p[j-1][i]];
}
}
}
int bl(int x,int d){
int k=LOG-1;
while (k>=0){
if ((1<<k)<=d){
d-=1<<k;
x=p[k][x];
}
k--;
}
return x;
}
void dfs(int x,int y){
for (auto [i,w]:a[x]){
if (i==y)continue;
dfs(i,x);
dp[0][x]=min(dp[0][x],dp[0][i]+w);
}
}
void makst(){
for (int j=1;j<LOG;j++){
for (int i=1;i<=n;i++){
li[j][i]=li[j-1][i]+li[j-1][p[j-1][i]];
}
}
for (int j=1;j<LOG;j++){
for (int i=1;i<=n;i++){
dp[j][i]=min(dp[j-1][i],dp[j-1][p[j-1][i]]+li[j-1][i]);
}
}
}
int dis(int x,int d){
int k=LOG-1;
int c=0;
int ans=inf;
while (k>=0){
if (d>=(1<<k)){
ans=min(ans,c+dp[k][x]);
c+=li[k][x];
x=p[k][x];
d-=1<<k;
}
k--;
}
ans=min(ans,c+dp[0][x]);
return ans;
}
void solve(){
int s,q,e;
cin >> n >> s >> q >> e;
for (int i=0;i<n-1;i++){
cin >> x >> y >> w;
a[x].push_back({y,w});
a[y].push_back({x,w});
in[{x,y}]=i;
in[{y,x}]=i;
it[i]={x,y};
}
for (int i=1;i<=n;i++){
dp[0][i]=inf;
}
for (int i=0;i<s;i++){
cin >> x;
sh[x]=1;
dp[0][x]=0;
}
queue<int>o;
o.push(e);
vi[e]=1;
di[e]=1;
while (o.size()){
int h=o.front();
o.pop();
for (auto [i,w]:a[h]){
if (vi[i])continue;
vi[i]=1;
di[i]=di[h]+1;
li[0][i]=w;
p[0][i]=h;
o.push(i);
}
}
makest();
dfs(e,0);
for (int i=1;i<=n;i++){
if (dp[0][i]<inf){
av[i]=1;
}
vi[i]=0;
}
makst();
// cout << dis(5,1) << endl;
for (int i=0;i<q;i++){
int j,k;
cin >> k >> j;
k--;
x=it[k].fi,y=it[k].se;
if (di[x]>di[y])swap(x,y);
if (di[y]>di[j]){
cout << "escaped" << endl;
continue;
}
if (bl(j,di[j]-di[y])!=y or bl(j,di[j]-di[x])!=x){
cout << "escaped" << endl;
continue;
}
if (av[y]){
cout << dis(j,di[j]-di[y]) << endl;
}
else{
cout << "oo" << endl;
}
}
}
signed main()
{
// #ifndef ONLINE_JUDGE
// freopen("input.txt","r" ,stdin);
// freopen("output.txt","w",stdout);
// #endif
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);//DO NOT USE IN INTERACTIVE
cout << fixed << setprecision(9);
srand(time(0));
// int t=1;
// cin >> t;
for (int _=1;_<=t;_++){
solve();
q++;
}
}
