#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx,avx2")
//#pragma GCC target("popcnt")
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MAX=1e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
const ldb eps=1e-6;
const ldb PI=acos(-1.0);
const int dir[4][2]={{-1,0},{0,1},{1,0},{0,-1}};
template<typename T>
using vvector = vector<vector<T>>;
void dfs1(int v,int p,vvector<pll> &G,vector<ll> &h,vector<ll> &nsp,vvector<ll> &spt,vector<bool> &sp,vector<ll> &wh) {
spt[v][0]=p;
for (int k=1;k<20;k++) {
spt[v][k]=spt[spt[v][k-1]][k-1];
}
h[v]=h[p]+1;
nsp[v]=(sp[v]?0:oo);
for (auto [i,w]:G[v]) {
if (i==p) continue;
wh[i]=wh[v]+w;
dfs1(i,v,G,h,nsp,spt,sp,wh);
nsp[v]=min(nsp[i]+w,nsp[v]);
}
}
void dfs2(int v,int p,vvector<pll> &G,vvector<ll> &nspt,vvector<ll> &spt,vector<ll> &nsp,vector<ll> &h,vector<ll> &wh) {
nspt[v][0]=nsp[v]-wh[v];
for (int i=1;i<20;i++) nspt[v][i]=min(nspt[v][i-1],nspt[spt[v][i-1]][i-1]);
for (auto [i,w]:G[v]) {
if (i==p) continue;
dfs2(i,v,G,nspt,spt,nsp,h,wh);
}
}
int lca(int a,int b,vector<ll> &h,vvector<ll> &spt) {
if (h[a]<h[b]) swap(a,b);
int x=h[a]-h[b];
for (int i=19;i>=0;i--) {
if (x>=(1<<i)) {
x-=(1<<i);
a=spt[a][i];
}
}
if (a==b) return a;
for (int i=19;i>=0;i--) {
if (spt[a][i]!=spt[b][i]) {
a = spt[a][i];
b = spt[b][i];
}
}
return spt[a][0];
}
int main() {
speed;
int n,s,q,r;
cin>>n>>s>>q>>r;
vvector<pll> G(n+1);
vector<bool> sp(n+1);
vector<pii> e(n);
for (int i=1;i<n;i++) {
int a,b,w;
cin>>a>>b>>w;
e[i]={a,b};
G[a].emplace_back(b,w);
G[b].emplace_back(a,w);
}
for (int i=0;i<s;i++) {
int x;
cin>>x;
sp[x]=true;
}
vector<ll> h(n+1),nsp(n+1),wh(n+1);
vvector<ll> spt(n+1,vector<ll>(20));
dfs1(r,0,G,h,nsp,spt,sp,wh);
vvector<ll> nspt(n+1,vector<ll>(20));
dfs2(r,0,G,nspt,spt,nsp,h,wh);
while (q--) {
int eid,x;
cin>>eid>>x;
if (h[e[eid].F]>h[e[eid].S]) swap(e[eid].F,e[eid].S);
// cout<<x<<" "<<eid<<" "<<e[eid].F<<" "<<e[eid].S<<" x eid e\n";
if (lca(x,e[eid].S,h,spt)!=e[eid].S) cout<<"escaped\n";
else {
ll ans=nsp[x]-wh[x];
ll d = h[x]-h[e[eid].S]+1;
int tx=x;
for (int i=19;i>=0;i--) {
if (d>=(1<<i)) {
ans=min(ans,nspt[x][i]);
x = spt[x][i];
d-=(1<<i);
}
}
ans += wh[tx];
if (ans>=oo) cout<<"oo\n";
else cout<<ans<<"\n";
}
}
return 0;
}
