#include<iostream>
#include<vector>
#include<queue>
#include<stack>
#include<algorithm>
#include<limits.h>
#include<math.h>
#include<map>
#include<set>
#include<unordered_map>
#include<unordered_set>
#include<iomanip>
#include<cstring>
#include<random>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
using namespace std;
int n,s,q,root;
bool has_shop[100000];
vector<pair<int,int>>nodes[100000];
vector<pair<int,int>>conns;
int par[100000][20];
int depth[100000];
ll depthw[100000];
ll nrd1[100000],nrd2[100000];
int nrc1[100000],nrc2[100000];
ll nru[100000][20];
void dfs1(int node){
for(int i=1;i<20;i++)
par[node][i]=par[par[node][i-1]][i-1];
nrc1[node]=-1;
nrc2[node]=-1;
nrd1[node]=1e18;
nrd2[node]=1e18;
if(has_shop[node])
nrd1[node]=0;
for(auto[ne,w]:nodes[node]){
if(ne==par[node][0])
continue;
par[ne][0]=node;
depth[ne]=depth[node]+1;
depthw[ne]=depthw[node]+w;
dfs1(ne);
if(nrd1[ne]+w<nrd1[node]){
nrc2[node]=nrc1[node];
nrd2[node]=nrd1[node];
nrd1[node]=nrd1[ne]+w;
nrc1[node]=ne;
}else if(nrd1[ne]+w<nrd2[node]){
nrd2[node]=nrd1[ne]+w;
nrc2[node]=ne;
}
}
}
void dfs2(int node){
for(auto[ne,w]:nodes[node]){
if(ne==par[node][0])
continue;
if(nrc1[node]==ne)
nru[ne][0]=w+nrd2[node];
else
nru[ne][0]=w+nrd1[node];
for(int i=1;i<20;i++)
nru[ne][i]=min(nru[ne][i-1],nru[par[ne][i-1]][i-1]+depthw[ne]-depthw[par[ne][i-1]]);
dfs2(ne);
}
}
int get_par(int node,int up){
for(int i=19;i>=0;i--)
if(up&(1<<i))
node=par[node][i];
return node;
}
// is a sub b?
bool is_sub(int a,int b){
return depth[a]>=depth[b]&&get_par(a,depth[a]-depth[b])==b;
}
void solve(){
cin>>n>>s>>q>>root;
root--;
for(int i=1;i<n;i++){
int a,b,w;
cin>>a>>b>>w;
a--;b--;
nodes[a].emplace_back(b,w);
nodes[b].emplace_back(a,w);
conns.emplace_back(a,b);
}
for(int i=0;i<s;i++){
int a;
cin>>a;
has_shop[a-1]=true;
}
par[root][0]=root;
dfs1(root);
dfs2(root);
while(q--){
int bc,node;
cin>>bc>>node;
node--;bc--;
int bn=conns[bc].first;
if(par[conns[bc].second][0]==conns[bc].first)
bn=conns[bc].second;
if(!is_sub(node,bn)){
cout<<"escaped\n";
continue;
}
ll res=nrd1[node];
ll len=0;
for(int p=19;p>=0;p--){
if((1<<p)<=depth[node]-depth[bn]){
res=min(res,nru[node][p]+len);
len+=depthw[node];
node=par[node][p];
len-=depthw[node];
}
}
if(res>=1e18)
cout<<"oo\n";
else
cout<<res<<"\n";
}
}
int main(){
ios::sync_with_stdio(false);cout.tie(NULL);cin.tie(NULL);
//freopen("/Users/jakob/cp_testing/test.txt","r",stdin);freopen("output.out","w",stdout);
int t=1;//cin>>t;
while(t--)solve();
return 0;
}
/*
5 2 3 1
1 2 3
1 3 2
3 4 1
3 5 2
2
4
2 2
2 5
4 5
escaped
3
oo
10 2 5 4
7 2 3
4 8 3
9 10 1
6 7 3
9 2 3
10 1 2
8 2 2
5 2 1
3 8 2
8
7
2 1
1 5
8 4
6 2
7 7
8
escaped
esacped
escaped
0
*/
