#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define inf LLONG_MAX
#define f first
#define s second
const int mx = 1e5+5, ml = 17;
int n, sh, q, e, tin[mx], tout[mx], cnt;
ll d[mx], dp[mx], up[ml][mx], best[ml][mx]; bool shop[mx];
pii edges[mx]; vector<pii> adj[mx];
ll dfs1(int node){
tin[node] = cnt++; ll ret = ((shop[node]) ? d[node] : inf);
for (int l = 1; l < ml; l++) up[l][node] = up[l-1][up[l-1][node]];
for (pii nxt : adj[node])
if (nxt.f != up[0][node])
d[nxt.f] = d[node]+nxt.s, up[0][nxt.f] = node, ret = min(ret, dfs1(nxt.f));
tout[node] = cnt-1; dp[node] = ((ret == inf) ? ret : ret-d[node]*2); return ret;
}
int main() {
cin >> n >> sh >> q >> e;
for (int i = 1; i < n; i++){
int a, b, w; cin >> a >> b >> w;
adj[a].push_back({b, w});
adj[b].push_back({a, w});
edges[i] = {a, b};
}for (int i = 0; i < sh; i++) { int a; cin >> a; shop[a] = 1; }
memset(best, 0x3f, sizeof(best)); dfs1(e);
for (int i = 1; i <= n; i++) best[0][i] = dp[up[0][i]];
for (int l = 1; l < ml; l++)
for (int i = 1; i <= n; i++)
best[l][i] = min(best[l-1][i], best[l-1][up[l-1][i]]);
while (q--){
int i, r; cin >> i >> r; ll ans = dp[r]; int curr = r;
int root = ((up[0][edges[i].f] == edges[i].s) ? edges[i].f : edges[i].s);
if (!(tin[root] <= tin[r] and tout[root] >= tout[r])) cout<<"escaped"<<endl;
else if (dp[root] == inf) cout<<"oo"<<endl;
else{
for (int l = ml-1; l >= 0; l--)
if (d[up[l][curr]] >= d[root])
ans = min(ans, best[l][curr]), curr = up[l][curr];
cout<<ans+d[r]<<endl;
}
}
}
