#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define x first
#define y second
#define getbit(u,i) ((u>>i)&1)
#define all(x) x.begin(),x.end()
#define N 200001
using namespace std;
typedef pair<int,int> ii;
typedef pair<double,double> dd;
struct node
{
int val,lazy;
} tree[4*N];
int n,s,e,q,a[N],num[N],tail[N],h[N],p[N][18],cnt,rev[N],d[N],ans[N];
vector<ii> g[N],Q[N];
ii ed[N];
void down(int id,int l,int r)
{
tree[id].val+=tree[id].lazy;
if(l!=r)
{
tree[id*2].lazy+=tree[id].lazy;
tree[id*2+1].lazy+=tree[id].lazy;
}
tree[id].lazy=0;
}
void update(int id,int l,int r,int u,int v,int val)
{
down(id,l,r);
if(l>v||r<u||l>r||u>v) return;
if(l>=u&&r<=v)
{
tree[id].val+=val;
if(l!=r)
{
tree[id*2].lazy+=val;
tree[id*2+1].lazy+=val;
}
return;
}
int m=(l+r)/2;
update(id*2,l,m,u,v,val);
update(id*2+1,m+1,r,u,v,val);
tree[id].val=min(tree[id*2].val,tree[id*2+1].val);
}
int get(int id,int l,int r,int u,int v)
{
down(id,l,r);
if(l>v||r<u||l>r||u>v) return LLONG_MAX;
if(l>=u&&r<=v) return tree[id].val;
int m=(l+r)/2;
return min(get(id*2,l,m,u,v),get(id*2+1,m+1,r,u,v));
}
void dfs(int u,int pre)
{
num[u]=++cnt;
rev[cnt]=u;
h[u]=h[pre]+1;
p[u][0]=pre;
for(int i=1;i<=17;i++) p[u][i]=p[p[u][i-1]][i-1];
for(ii v : g[u])
{
if(v.x==pre) continue;
d[v.x]=d[u]+v.y;
dfs(v.x,u);
}
tail[u]=cnt;
}
int lca(int u,int v)
{
if(h[u]<h[v]) swap(u,v);
for(int i=17;i>=0;i--)
{
if(h[p[u][i]]>=h[v]) u=p[u][i];
}
if(u==v) return u;
for(int i=17;i>=0;i--)
{
if(p[u][i]!=p[v][i])
{
u=p[u][i];
v=p[v][i];
}
}
return p[u][0];
}
void reroot(int u,int pre)
{
// cout<<u<<'\n';
// for(int i=1;i<=s;i++) cout<<get(1,1,s,i,i)<<' ';
// cout<<'\n';
for(ii c : Q[u])
{
int cur=ed[c.x].x;
// if(u==5)cout<<cur<<' ';
if(lca(u,cur)!=cur) ans[c.y]=-1;
else
{
int l=lower_bound(a+1,a+s+1,num[cur])-a;
int r=upper_bound(a+1,a+s+1,tail[cur])-a-1;
if(l>r) ans[c.y]=-2;
else ans[c.y]=get(1,1,s,l,r);
}
}
for(ii v : g[u])
{
if(v.x==pre) continue;
int l=lower_bound(a+1,a+s+1,num[v.x])-a;
int r=upper_bound(a+1,a+s+1,tail[v.x])-a-1;
// if(v.x==3) cout<<num[3]<<' '<<l<<' '<<r<<'\n';
update(1,1,s,1,s,v.y);
update(1,1,s,l,r,-2*v.y);
reroot(v.x,u);
update(1,1,s,1,s,-v.y);
update(1,1,s,l,r,2*v.y);
}
}
signed main()
{
if(fopen("demo.inp","r"))
{
freopen("demo.inp","r",stdin);
freopen("demo.out","w",stdout);
}
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n>>s>>q>>e;
for(int i=1;i<n;i++)
{
int u,v,w;
cin>>u>>v>>w;
ed[i]={u,v};
g[u].pb({v,w});
g[v].pb({u,w});
}
dfs(e,0);
for(int i=1;i<n;i++)
{
if(h[ed[i].x]<h[ed[i].y]) swap(ed[i].y,ed[i].x);
}
for(int i=1;i<=s;i++) {cin>>a[i]; a[i]=num[a[i]];}
// cout<<upper_bound(a+1,a+s+1,3)-a-1;
// return 0;
sort(a+1,a+s+1);
for(int i=1;i<=s;i++) update(1,1,s,i,i,d[rev[a[i]]]);
for(int i=1;i<=q;i++)
{
int k,r;
cin>>k>>r;
Q[r].pb({k,i});
}
reroot(e,0);
for(int i=1;i<=q;i++)
{
if(ans[i]==-1) cout<<"escaped\n";
else if(ans[i]==-2) cout<<"oo\n";
else cout<<ans[i]<<'\n';
}
}
