//#pragma GCC optimize("O3,unroll-loops,Ofast")
//#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
using namespace std;
// using namespace __gnu_pbds;
#define MAX 500005
#define pb push_back
// #define mp make_pair
#define int long long
#define f first
#define s second
#define vi vector<int>
#define pii pair<int,int>
#define si set<int>
#define vpii vector<pair<int,int>>
const int mod = 1e9+7;
const int INF = 1e18;
// myMap.begin()->first : key
// myMap.begin()->second : value
int epow(int a,int b){int ans=1;while(b){if(b&1) ans*=a;a*=a;b>>=1;ans%=mod;a%=mod;}return ans%mod;}
int gcd(int a,int b) {if(a<b)swap(a,b);while(b){int tmp=b;b=a%b;a=tmp;}return a;}
int mul(int a,int b){return ((a%mod)*(b%mod))%mod;}
int sum(int a,int b){return ((a%mod)+(b%mod))%mod;}
//typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>ordered_set;
// typedef
// tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>ordered_multiset;
vpii adj[MAX];
vi is_shop(MAX),tin(MAX),tout(MAX),arr(MAX,INF),dep(MAX),ans(MAX);
vector<array<int,3>> edges(MAX);
int timer=1;
void dfs(int node,int par){
tin[node]=timer++;
if(is_shop[node]) arr[node]=dep[node];
for(auto u : adj[node]){
if(u.f==par) continue;
dep[u.f]=dep[node]+u.s;
dfs(u.f,node);
arr[node]=min(arr[node],arr[u.f]);
}
tout[node]=timer-1;
ans[node]=arr[node]-2*dep[node];
}
int p[MAX][22],mn[MAX][22];
void dfs2(int node,int par){
for(int i=1;i<=20;i++){
p[node][i]=p[p[node][i-1]][i-1];
mn[node][i]=min(mn[node][i-1],mn[p[node][i-1]][i-1]);
}
for(auto u : adj[node]){
if(u.f==par) continue;
p[u.f][0]=node; mn[u.f][0]=ans[node];
dfs2(u.f,node);
}
}
void solve(){
int n,s,q,e; cin>>n>>s>>q>>e;
for(int i=1;i<n;i++){
int a,b,c; cin>>a>>b>>c;
adj[a].pb({b,c}); adj[b].pb({a,c});
edges[i]={a,b,c};
}
for(int i=1;i<=s;i++){
int a; cin>>a;
is_shop[a]=1;
}
dfs(e,0); dfs2(e,0);
for(int i=1;i<n;i++){
if(tin[edges[i][0]]>tin[edges[i][1]]) swap(edges[i][0],edges[i][1]);
}
// for(int i=1;i<=n;i++) cout<<ans[i]<<" "<<arr[i]<<endl;
// for(int i=1;i<=n;i++) cout<<mn[i][1]<<" ";cout<<endl;
// cout<<dep[7]<<endl;
while(q--){
int I,R,cvp; cin>>I>>R;
cvp=ans[R];
bool flag1 = (tin[e]>=tin[edges[I][1]] && tin[e]<=tout[edges[I][1]]);
bool flag2 = (tin[R]>=tin[edges[I][1]] && tin[R]<=tout[edges[I][1]]);
if( !(flag1^flag2) ){
cout<<"escaped\n"; continue;
}
int curr=R;
for(int i=20;i>=0;i--){
if(tin[p[curr][i]]>=tin[edges[I][1]]) cvp=min(cvp,mn[curr][i]), curr=p[curr][i];
}
cvp+=dep[R];
if(cvp>1e14) cout<<"oo\n";
else cout<<cvp<<endl;
}
}
int32_t main(/*int32_t argc, char* argv[]*/){
std::ios_base::sync_with_stdio(0); std::cin.tie(0);
// freopen("disconnected.in", "r", stdin);
// freopen("disconnected.out", "w", stdout);
int t=1;
// cin >> t;
while (t--) solve();
return 0;
}
