#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<ll,int>
#define X first
#define Y second
const int N=1e5+5;
const int K=22;
const ll oo=(long double)1e18+1;
int n,request,s,e,banned,x,y,z;
int a[N],b[N],c[N];
ll d[N];
bool HaveShop[N];
vector <pii> adj[N];
namespace sub2
{
ll res;
priority_queue <pii,vector<pii>,greater<pii>> pq;
void dijkstra(int u,int banned)
{
while (!pq.empty()) pq.pop();
ll dist;
for (int i=1;i<=n;i++)
d[i]=oo;
d[u]=0;
pq.push(make_pair(0,u));
while (!pq.empty())
{
dist=pq.top().X;
u=pq.top().Y;
pq.pop();
if (dist>d[u]) continue;
if (u==e)
{
cout << "escaped" << '\n';
return;
}
for (pii v:adj[u])
if (v.Y!=banned and d[v.X]>dist+c[v.Y])
{
d[v.X]=dist+c[v.Y];
pq.push(make_pair(d[v.X],v.X));
}
}
res=oo;
for (int i=1;i<=n;i++)
if (HaveShop[i]) res=min(res,d[i]);
if (res==oo) cout << "oo" << '\n';
else cout << res << '\n';
}
void solve()
{
while (request--)
{
cin >> banned >> x;
dijkstra(x,banned);
}
}
}
namespace sub3
{
int h;
int H[N],p[N][K];
bool check_E[N];
void pre_dfs(int u,int root)
{
check_E[u]=(u==e);
for (pii v:adj[u])
if (v.Y!=root)
{
H[v.X]=H[u]+1;
p[v.X][0]=u;
pre_dfs(v.X,v.Y);
check_E[u]|=check_E[v.X];
}
}
int lca(int a,int b)
{
if (H[a]<H[b]) swap(a,b);
for (int j=h;j>=0;j--)
if (H[p[a][j]]>=H[b])
{
a=p[a][j];
}
if (a==b) return a;
for (int j=h;j>=0;j--)
if (p[a][j]!=p[b][j])
{
a=p[a][j];
b=p[b][j];
}
return p[a][0];
}
void solve()
{
H[1]=1;
pre_dfs(1,-1);
for (int i=1;i<n;i++)
if (H[a[i]]>H[b[i]]) swap(a[i],b[i]);
h=31-__builtin_clz(n);
for (int j=1;j<=h;j++)
for (int i=1;i<=n;i++)
p[i][j]=p[p[i][j-1]][j-1];
while (request--)
{
cin >> banned >> x;
if (lca(x,b[banned])==b[banned])
{
if (check_E[b[banned]]) cout << "escaped" << '\n';
else cout << 0 << '\n';
}
else
{
if (check_E[b[banned]]==false) cout << "escaped" << '\n';
else cout << 0 << '\n';
}
}
}
}
int main()
{
ios_base::sync_with_stdio(NULL);
cin.tie(NULL); cout.tie(NULL);
cin >> n >> s >> request >> e;
for (int i=1;i<n;i++)
{
cin >> a[i] >> b[i] >> c[i];
adj[a[i]].push_back(make_pair(b[i],i));
adj[b[i]].push_back(make_pair(a[i],i));
}
for (int i=1;i<=s;i++)
{
cin >> x;
HaveShop[x]=true;
}
if (s==n) sub3::solve();
else sub2::solve();
}
