#include<bits/stdc++.h>
#define int long long
#define str string
#define task "strdel"
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define se second
#define fi first
#define ffi fi.fi
#define sfi se.fi
#define sse se.se
#define fse fi.se
#define lt(i, c, d) for(int i = c; i <= d; ++i)
#define fl(i, c, d) for(int i = d; i >= c; --i)
#define pb push_back
#define emb emplace_back
#define em emplace
using namespace std;
const int N=1e5+5,lg=20,mod=1e9+7;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int Rand(int u,int v){
return u+rd()%(v-u+1);
}
int h[N],up[N][lg+5];
int n,S,q,e,g[N],tin[N],tout[N],t;
long long k[N],f[N][lg+5],d[N];
vector<ii>a[N];
void dfs(int u,int cha){
// cout <<u<<" ";
tin[u]=++t;
k[u]=1e18;
if(g[u])k[u]=d[u];
for(auto v:a[u]){
if(v.fi==cha)continue;
up[v.fi][0]=u;
h[v.fi]=h[u]+1;
d[v.fi]=d[u]+v.se;
// cout<<u<<" "<<v.fi<<" "<<up[v.fi][0]<<'\n';
dfs(v.fi,u);
k[u]=min(k[u],k[v.fi]);
}
tout[u]=t;
}
long long lca(int u,int v,int goc){
// cout<<ans<<" ";
if(h[u]<h[v])swap(u,v);
long long ans=k[u]-d[u];
// cout << u<<" "<<v<<'\n';
for(int j=lg;j>=0;--j){
if(h[u]-h[v]>=(1<<j)){
ans=min(ans,f[u][j]+d[goc]);
// cout << u<<" "<<j <<" "<<f[u][j]<<" "<<d[u]<<'\n';
u=up[u][j];
}
}
return ans;
}
void dfs2(int u,int cha){
for(ii v:a[u]){
if(v.fi==cha)continue;
// k[v.fi]=min(k[v.fi],k[u]);
f[v.fi][0]=k[u]-2*d[u];
// cout<<v.fi<<" "<<k[u]<<" "<<d[u]<<'\n';
dfs2(v.fi,u);
}
}
ii b[N];
void solve(){
cin >>n >>S >>q >> e;
// for(int i=1;i<=n;++i)for(int j=0;j<=lg;++j)f[i][j]=1e18;
for(int i=1;i<n;++i){
int u,v,w;
cin >> u >> v >> w;
a[u].emb(v,w);
a[v].emb(u,w);
b[i]={u,v};
}
while(S--){
int u;
cin >> u;
g[u]=1;
}
dfs(e,-1);
dfs2(e,-1);
for(int j=1;j<=lg;++j){
for(int i=1;i<=n;++i){
up[i][j]=up[up[i][j-1]][j-1];
f[i][j]=min(f[i][j-1],f[up[i][j-1]][j-1]);
}
}
// f[e][0]=1e18;
// for(int i=1;i<=n;++i)cout<<d[i]<<" "<<k[i]<<" "<<f[i][2]<<'\n'; ;
while(q--){
int i,y;
cin >> i >> y;
int u=y,v,goc=y;
if(h[b[i].fi]>h[b[i].se])v=b[i].fi;
else v=b[i].se;
if(tin[v]<=tin[u]&&tout[u]<=tout[v]){
long long ans=lca(u,v,goc);
if(ans>=1e15)cout<<"oo";
else{
cout<<ans;
}
}
else cout <<"escaped";
if(q)cout<<'\n';
}
}
main()
{
srand(time(0));
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
if(fopen(task".inp","r")){
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int t=1;
// cin >> t;
while(t--){
solve();
if(t)cout<<'\n';
}
}
