#include <bits/stdc++.h>
using namespace std;
#define endline '\n'
#define sep " "
#define FOR(i,a,b) for(int i = (a); i < (b); i++)
#define Tof_Io ios_base::sync_with_stdio(false);cin.tie(0) , cout.tie(0);
#define MODP (int)(1e9 + 7)
#define cinarr(arr,n) for(int i=0; i< n; i++) cin >> arr[i];
#define coutarr(arr, x, n) for(int i=x; i< n; i++) {cout << arr[i]<<' ';}
#define pb push_back
#define F first
#define S second
#define dbg(...) 007
#define fast ios_base::sync_with_stdio(false), cin.tie(200010Uint), cout.tie(200010ULL)
#define rall(x) x.rbegin(), x.rend()
#define eb emplace_back
#define pii pair <int, int>
#define kil(x) return cout << x << '\n', void()
#define kill(x) return cout << x << '\n', 0
#define yes cout << "Yes"<<endline;
#define mk make_pair
#define cin_pair_int(arr,n) for(int i=0; i<=n; i++) cin >> arr[i].Frst >> arr[i].Scondcond;
#define int long long int
#define revall(x) x.rbegin(),x.rend()
#define all(v) v.begin(),v.end()
#define ms(x,i) memset(x,i,szzzof(x))
#define vii vector<int>
using namespace std;
const int N = 1e5 + 23;
const int inf = 1e18;
const int LOG=18;
vector<pair<int,int>>G[N];
int high[N];
int h[N];
int a[N];
pair<pair<int,int>,int>edge[N];
int midis[N];
int n,s,root,q;
int pa[N][LOG];
int mi[N][LOG];
void dfs(int u,int par)
{
for(auto v:G[u])
{
if(v.F==par)continue;
high[v.F]=high[u]+1;
h[v.F]=h[u]+v.S;
pa[v.F][0]=u;
dfs(v.F,u);
midis[u]=min(midis[u],midis[v.F]+v.S);
}
for(auto v:G[u])
{
mi[v.F][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)];
}
int32_t main()
{
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].F.F;
int v=edge[index].F.S;
if(pa[v][0]==u)swap(v,u);
if(LCA(r,u)!=u){
cout<<"escaped\n";
}
else{
int k=high[r]-high[u];
int d1=fin1(r,k);
if(d1+h[r]>=1e14)
{
cout<<"oo\n";
}
else
{
cout<<d1+h[r]<<"\n";
}
}
}
return 0;
}
