#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) //cout << y << " " << #x << endl;
#define show2(x,y,i,j) //cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) //cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;
vector<pii>adj[100005];
int two[25][100005];
int mini[25][100005];
int in[100005];
int out[100005];
int ptr=0;
int d[100005];
bool shop[100005];
int dp[100005];
int h[100005];
void dfs(int index, int par){
in[index]=++ptr;
if(shop[index]) dp[index]=h[index];
for(auto it:adj[index]){
if(it.first==par) continue;
d[it.first]=d[index]+1;
h[it.first]=h[index]+it.second;
dfs(it.first,index);
dp[index]=min(dp[index],dp[it.first]);
}
out[index]=ptr;
}
void dfs2(int index, int par){
for(int x=0;x<20;x++){
two[x+1][index]=two[x][two[x][index]];
mini[x+1][index]=min(mini[x][index],mini[x][two[x][index]]);
}
for(auto it:adj[index]){
if(it.first==par) continue;
two[0][it.first]=index;
mini[0][it.first]=dp[index]-2*h[index];
dfs2(it.first,index);
}
}
int lift(int a, int b){
//a is road b is node
int diff=d[b]-d[a];
int ans=dp[b]-h[b];
int hold=b;
for(int x=0;x<20;x++){
if(diff&(1<<x)){
ans=min(ans,mini[x][b]+h[hold]);
b=two[x][b];
}
}
return ans;
}
void solve(){
int n,s,q,e;
cin >> n >> s >> q >> e;
int temp,temp2,temp3;
pii edge[n-1];
for(int x=0;x<n-1;x++){
cin >> temp >> temp2 >> temp3;
adj[temp].push_back({temp2,temp3});
adj[temp2].push_back({temp,temp3});
edge[x]={temp,temp2};
}
for(int x=0;x<s;x++){
cin >> temp;
shop[temp]=true;
}
for(int x=0;x<=n;x++){
dp[x]=1e15;
for(int y=0;y<25;y++) mini[y][x]=1e15;
}
dfs(e,-1);
dfs2(e,-1);
int road,node;
for(int x=0;x<q;x++){
cin >> road >> node;
road--;
//node is in subtree of road
if(d[edge[road].first] < d[edge[road].second]){
temp=edge[road].second;
}
else{
temp=edge[road].first;
}
show(temp,temp);
show3(in[temp],in[temp],out[temp],out[temp],in[node],in[node]);
if(in[temp]<=in[node]&&out[temp]>=in[node]){
int ans=lift(temp,node);
if(ans>1e12){
cout << "oo\n";
}
else{
cout << ans << "\n";
}
}
else cout << "escaped\n";
}
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
//freopen("redistricting.in", "r", stdin);
//freopen("redistricting.out", "w", stdout);
int t=1;
//cin >> t;
while(t--){
solve();
}
}
