#include<bits/stdc++.h>
using namespace std;
#define task "comseq"
#define ii pair<ll,ll>
#define fi first
#define se second
#define int long long
#define ll long long
#define ld double
#define mp make_pair
#define lg2 20
#define iii pair<int,ii>
#define iiii pair<ii,ii>
#define fii fi.fi
#define fis fi.se3
#define sfi se.fi
#define see se.se
#define base 29
int dx[]={0LL,0LL,1,-1,1,1,-1,-1};
int dy[]={1,-1,0LL,0LL,1,-1,1,-1};
const int maxn=1e5+1;
const int mod=1e9+7;
int d[maxn],n,S,q,e,P_min[maxn][lg2+1],dp[maxn],P[maxn][lg2+1],h[maxn],dist[maxn];
ii b[maxn];
vector<ii>a[maxn];
void dfs(int u,int cha)
{
if(d[u])dp[u]=dist[u];
else dp[u]=1e18;
for(ii v:a[u])
{
if(v.fi==cha)continue;
P[v.fi][0]=u;
h[v.fi]=h[u]+1;
dist[v.fi]=dist[u]+v.se;
dfs(v.fi,u);
dp[u]=min(dp[u],dp[v.fi]);
}
for(ii v:a[u])
{
if(v.fi==cha)continue;
P_min[v.fi][0]=dp[u]-2*dist[u];
// cout<<dp[u]<<" "<<dp[u]-2*dist[u]<<" "<<u<<'\n';
}
}
void build_lca(){
for(int j=1;j<=lg2;j++){
for(int i=1;i<=n;i++)
if(P[i][j-1]!=0){
P[i][j]=P[P[i][j-1]][j-1];
P_min[i][j]=min(P_min[i][j-1],P_min[P[i][j-1]][j-1]);
}
}
}
int lca(int u,int v){
if(h[u]<h[v])swap(u,v);
for(int i=lg2;i>=0;i--){
if(h[u]-h[v]>=(1<<i))
u=P[u][i];
}
if(u==v){
return u;
}
for(int i=lg2;i>=0;i--){
if(P[u][i]!=P[v][i]){
u=P[u][i];
v=P[v][i];
}
}
return P[u][0];
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
if(fopen(task".inp","r")){
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);}
cin>>n>>S>>q>>e;
for(int i=1;i<n;i++)
{
int u,v,w;
cin>>u>>v>>w;
a[u].push_back({v,w});
a[v].push_back({u,w});
b[i]={u,v};
}
for(int i=1;i<=S;i++)
{
int c;cin>>c;
d[c]=1;
}
dfs(e,-1);
build_lca();
//cout<<P_min[1][2]<<'\n';
while(q--)
{
int I,R;
cin>>I>>R;
int goc=R;
int u=b[I].fi,v=b[I].se;
if(h[u]>h[v])swap(u,v);
if(lca(R,v)!=v)
{
cout<<"escaped"<<'\n';
}
else
{
int ans=dp[goc]-dist[goc];
for(int j=lg2;j>=0;j--)
{
if((1<<j)<=h[R]-h[v])
{
ans=min(ans,P_min[R][j]+dist[goc]);
R=P[R][j];
}
}
if(ans>=1e15)cout<<"oo"<<'\n';
else
cout<<ans<<'\n';
}
}
}
