#include <bits/stdc++.h>
using namespace std;
#define file "file"
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
const int N=1e5+5;
int n,s,q,H,up[N][22],d[N],ss[N];
long long h[N];
vector<pii> E[N], edge;
bool a[N];
void dfs(int u)
{
for (pii p : E[u])
{
int v=p.first; if (v==up[u][0]) continue;
up[v][0]=u; d[v]=d[u]+1; h[v]=h[u] + p.second;
for (int j=1;j<=20;j++) up[v][j]=up[up[v][j-1]][j-1];
dfs(v);
}
}
int lca(int u, int v)
{
if (d[u]!=d[v])
{
if (d[u] < d[v]) swap(u, v);
int k=d[u]-d[v];
for (int j=0;(1<<j) <= k;j++)
if ((k>>j) & 1) u=up[u][j];
}
if (u==v) return u;
int k=__lg(d[u]);
for (int j=k;j>=0;j--)
if (up[u][j]!=up[v][j]) u=up[u][j], v=up[v][j];
return up[u][0];
}
bool uni(int u, int v, int x)
{
if (lca(v, edge[x].second) != edge[x].second && lca(u, edge[x].second) != edge[x].second) return 1;
if (lca(v, edge[x].second) == edge[x].second && lca(u, edge[x].second) == edge[x].second) return 1;
return 0;
}
int main()
{
//freopen(file".inp", "r", stdin);
//freopen(file".out", "w", stdout);
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n>>s>>q>>H;
for (int i=1;i<n;i++)
{
int u,v,w; cin>>u>>v>>w; E[u].pb({v, w}); E[v].pb({u, w}); edge.pb({u, v});
}
for (int i=1;i<=s;i++) {int x; cin>>x; a[x]=1;}
h[0]=INT_MAX; dfs(1);
for (int i=0;i<edge.size();i++)
if (d[edge[i].first] > d[edge[i].second]) swap(edge[i].first, edge[i].second);
while (q--)
{
int x,u; cin>>x>>u; x--;
if (uni(u,H,x)) {cout<<"escaped\n"; continue;}
long long res=INT_MAX;
if (a[u]) {cout<<"0\n"; continue;}
for (int i=1;i<=n;i++) if (a[i]) res=min(res, h[u]+h[i]-2*h[lca(i,u)]);
if (res<INT_MAX) cout<<res<<'\n'; else cout<<"oo\n";
}
}
