#include <iostream>
#include <vector>
#define int long long
using namespace std;
const int mx=1000000000000000000;
struct edge{
int u,v,w;
}ed[100001];
int n,s,q,e,st[100001],en[100001],dp[100001],id,c[100001],u,d[100001],p[100001][20],mn[100001][20];
vector <pair <int, int> > ke[100001];
void dfs(int u, int p){
st[u]=++id;
if (!c[u])
dp[u]=mx;
for (auto v:ke[u])
if (v.first!=p){
d[v.first]=d[u]+v.second;
dfs(v.first,u);
dp[u]=min(dp[u],dp[v.first]+v.second);
}
en[u]=++id;
}
void dfs2(int u, int par){
for (auto v:ke[u])
if (v.first!=par){
p[v.first][0]=u;
mn[v.first][0]=dp[u];
dfs2(v.first,u);
}
}
bool isancestor(int i, int j){
return (st[i]<=st[j]&&en[i]>=en[j]);
}
void prep(){
for (int i=1;i<20;i++)
for (int j=1;j<=n;j++){
p[i][j]=p[p[i][j-1]][j-1];
mn[i][j]=min(mn[i][j-1],mn[p[i][j-1]][j-1]);
}
}
int f(int i, int j){
int res=dp[i];
for (int k=19;k>=0;k--)
if (p[i][k]&&d[p[i][k]]>d[j]){
res=min(res,mn[i][k]);
i=p[i][k];
}
res=min(res,dp[j]);
return res;
}
signed main(){
ios_base::sync_with_stdio(NULL);cin.tie(nullptr);
cin >> n >> s >> q >> e;
for (int i=1;i<n;i++){
cin >> ed[i].u >> ed[i].v >> ed[i].w;
ke[ed[i].u].push_back({ed[i].v,ed[i].w});
ke[ed[i].v].push_back({ed[i].u,ed[i].w});
}
for (int i=0;i<s;i++){
cin >> u;
c[u]=1;
}
dfs(e,e);
for (int i=1;i<=n;i++)
dp[i]-=d[i];
dfs2(e,e);
prep();
int i,r;
while (q--){
cin >> i >> r;
if (d[ed[i].u]<d[ed[i].v])
swap(ed[i].u,ed[i].v);
int u=ed[i].u;
if (!isancestor(u,r)){
cout << "escaped\n";
continue;
}
int res=f(r,u)+d[r];
if (res==mx)
cout << "oo\n";
else
cout << res << '\n';
}
}
