#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
#define fio ios_base::sync_with_stdio(0);cin.tie(0);
#define ll long long
#define ld long double
#define en exit(0);
#define pb push_back
#define fi first
#define se second
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int N = 1e5 + 5;
const int LOG = log2(N) + 2;
const ll INF = 1e18 + 5;
vector<pair<int,int> > edg;
vector<pair<int,int> > g[N];
bool shop[N];
ll dist[N], closest[N];
int par[N][LOG];
ll best[N][LOG];
int tin[N], tout[N], tt;
void dfs(int u, int p)
{
closest[u] = (shop[u] ? 0 : INF);
tin[u] = ++tt;
par[u][0] = p;
for(int i = 1;i < LOG;i++)
par[u][i] = par[par[u][i - 1]][i - 1];
for(auto [v, w] : g[u])
{
if(v != p)
{
dist[v] = dist[u] + w;
dfs(v, u);
closest[u] = min(closest[u], closest[v] + w);
}
}
tout[u] = tt;
}
void dfs2(int u, int p)
{
best[u][0] = (dist[u] - dist[p]) + closest[p];
for(int i = 1;i < LOG;i++)
{
int jumpi = par[u][i - 1];
ll d = dist[u] - dist[jumpi];
best[u][i] = min(best[u][i - 1], d + best[jumpi][i - 1]);
}
for(auto [v, w] : g[u])
if(v != p)
dfs2(v, u);
}
bool isanc(int u, int v)
{
return (tin[u] <= tin[v] && tout[v] <= tout[u]);
}
ll get_best(int r, int u)
{
ll cur = closest[r], d = 0;
for(int i = LOG - 1;i >= 0;i--)
{
int jump = par[r][i];
if(!isanc(jump, u))
{
cur = min(cur, d + best[r][i]);
d += dist[r] - dist[jump];
r = jump;
}
}
return cur;
}
int main()
{
fio
// ifstream cin("in.in");
int n, s, q, e;
cin >> n >> s >> q >> e;
edg.resize(n - 1);
for(int i = 0;i < n - 1;i++)
{
int u, v, w;
cin >> u >> v >> w;
g[u].pb({v, w});
g[v].pb({u, w});
edg[i] = {u, v};
}
for(int i = 1;i <= s;i++)
{
int p;
cin >> p;
shop[p] = 1;
}
dfs(e, e);
dfs2(e, e);
while(q--)
{
int i, r;
cin >> i >> r;
int u = edg[i - 1].fi, v = edg[i - 1].se;
if(dist[u] < dist[v])
swap(u, v);
if(isanc(u, r))
{
ll val = get_best(r, v);
if(val == INF)
cout << "oo";
else
cout << val;
}
else
cout << "escaped";
cout << "\n";
}
return 0;
}
