/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
*/
#include<bits/stdc++.h>
#define int long long
using namespace std;
#define all(x) x.begin(), x.end()
#define len(x) ll(x.size())
#define eb emplace_back
#define PI 3.14159265359
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define BIT(x,i) (1&((x)>>(i)))
#define MASK(x) (1LL<<(x))
#define task "tnc"
typedef long long ll;
const ll INF=1e18;
const int maxn=1e6+5;
const int mod=1e9+7;
const int mo=998244353;
using pi=pair<ll,ll>;
using vi=vector<ll>;
using pii=pair<pair<ll,ll>,ll>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
vector<pair<int,int>>G[maxn];
int high[maxn];
int h[maxn];
int a[maxn];
pair<pair<int,int>,int>edge[maxn];
int midis[maxn];
int n,s,root,q;
int pa[maxn][18];
int mi[maxn][18];
void dfs(int u,int par){
for(auto v:G[u]){
if(v.fi==par)continue;
high[v.fi]=high[u]+1;
h[v.fi]=h[u]+v.se;
pa[v.fi][0]=u;
dfs(v.fi,u);
midis[u]=min(midis[u],midis[v.fi]+v.se);
mi[v.fi][0]=midis[u]-h[u];
}
}
int LCA(int u,int v){
if(high[u]>high[v])swap(u,v);
int d=high[v]-high[u];
for(int j=18;j>=0;j--){
if((1<<j)&d){
v=pa[v][j];
}
}
if(u==v){
return u;
}
for(int j=18;j>=0;j--){
if(pa[u][j]!=pa[v][j] && pa[u][j]!=0){
u=pa[u][j];
v=pa[v][j];
}
}
return pa[u][0];
}
int fin(int u,int k){
for(int j=18;j>=0;j--){
if((1<<j)&k){
u=pa[u][j];
}
}
return u;
}
int fin1(int u,int k){
int d=midis[u]-h[u];
for(int j=18;j>=0;j--){
if((1<<j)&k){
d=min(d,mi[u][j]);
u=pa[u][j];
}
}
return d;
}
void init(){
for(int j=1;(1<<j)<=n;j++){
for(int i=1;i<=n;i++){
pa[i][j]=pa[pa[i][j-1]][j-1];
mi[i][j]=min(mi[i][j-1],mi[pa[i][j-1]][j-1]);
}
}
}
int getdist(int u,int v){
return high[u]+high[v]-2*high[LCA(u,v)];
}
signed main()
{
cin.tie(0),cout.tie(0)->sync_with_stdio(0);
cin>>n>>s>>q>>root;
for(int i=1;i<n;i++){
int u,v,w;
cin>>u>>v>>w;
edge[i]={{u,v},w};
G[u].pb({v,w});
G[v].pb({u,w});
}
for(int i=1;i<=n;i++){
midis[i]=INF;
}
for(int i=1;i<=s;i++){
cin>>a[i];
midis[a[i]]=0;
}
dfs(root,root);
init();
for(int i=1;i<=q;i++){
int index,r;
cin>>index>>r;
int u=edge[index].fi.fi;
int v=edge[index].fi.se;
if(pa[v][0]==u)swap(v,u);
if(getdist(r,u)+getdist(v,root)+1!=high[r]){
cout<<"escaped\n";
}
else{
int k=high[r]-high[u];
int d1=fin1(r,k);
if(d1+h[r]>=INF){
cout<<"oo\n";
}
else{
cout<<d1+h[r]<<"\n";
}
}
}
return 0;
}
