#include <bits/stdc++.h>
using namespace std;
#define fileio() freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define fastio() cin.tie(0), ios_base::sync_with_stdio(0)
#define sp " "
#define endl "\n"
#define pb push_back
#define pii pair<int, int>
#define st first
#define nd second
#define N 100005
#define LOGN 20
#define int long long
int dist[N], dep[N], mini[LOGN][N], par[LOGN][N], shop[N];
vector<pii> adj[N];
pii edge[N];
const int INF = 2e18 + 8, INF2 = 1e18 + 4;
int dfs(int node, int root, int d, int dd)
{
par[0][node] = root;
dist[node] = dd;
dep[node] = d;
int ans = INF;
if (shop[node]) ans = 0;
for (auto i : adj[node])
{
int curr = i.st, w = i.nd;
if (curr != root) ans = min(ans, dfs(curr, node, d + 1, dd + w) + w);
}
mini[0][node] = ans - dist[node];
return ans;
}
pii lca(int a, int b)
{
int ans = mini[0][a];
for (int i = LOGN - 1; i >= 0; i--)
if ((1<<i) <= dep[a] - dep[b]) ans = min(ans, mini[i + 1][a]), a = par[i][a];
if (a == b) return {a, ans};
return {-1, -1};
}
int32_t main()
{
fastio();
int n, s, q, e;
cin>>n>>s>>q>>e;
for (int i = 1; i < n; i++)
{
int u , v, w;
cin>>u>>v>>w;
adj[u].pb({v, w});
adj[v].pb({u, w});
edge[i] = {u, v};
}
for (int i = 1; i <= s; i++)
{
int num;
cin>>num;
shop[num] = 1;
}
int tmp = dfs(e, 0, 1, 0);
for (int i = 1; i < LOGN; i++)
{
for (int j = 1; j <= n; j++)
{
mini[i][j] = min(mini[i - 1][j], mini[i - 1][par[i - 1][j]]);
par[i][j] = par[i - 1][par[i - 1][j]];
}
}
for (int i = 1; i < n; i++)
{
int u = edge[i].st, v = edge[i].nd;
if (dep[u] < dep[v]) swap(edge[i].st, edge[i].nd);
//cout<<edge[i].st<<sp<<edge[i].nd<<endl;
}
while(q--)
{
int i, r;
cin>>i>>r;
int top = edge[i].st;
pii res = lca(r, top);
if (res.st == -1)
{
cout<<"escaped"<<endl;
continue;
}
int ans = res.nd + dist[r];
if (ans >= INF2) cout<<"oo\n";
else cout<<ans<<endl;
}
cerr<<"time taken : "<<(float)clock() / CLOCKS_PER_SEC<<"seconds\n";
}
