#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define pa pair<ll, ll>
#define fi first
#define se second
#define bit(mask, j) ((mask >> j) & 1)
const ll mod = 1e9 + 7;
const ll INF = 1e18;
//--------------------------------------------------------------------
ll n, s, q, E;
const ll N = 1e5 + 10;
vector<pa> g[N];
ll dx[N];
ll dp[N], f[N], h[N], up[N][18], dist[N][18];
void dfs(ll u, ll p) {
if(dx[u] == 1) dp[u] = f[u];
else dp[u] = INF;
for(auto e : g[u]) {
ll v = e.fi, w = e.se;
if(v == p) continue;
h[v] = h[u] + 1;
f[v] = f[u] + w;
up[v][0] = u;
FOR(i, 1, 17) {
up[v][i] = up[up[v][i - 1]][i - 1];
}
dfs(v, u);
dp[u] = min(dp[u], dp[v]);
}
}
void build_dist() {
FOR(u, 1, n) {
if(up[u][0] == 0 || dp[up[u][0]] == INF) dist[u][0] = INF;
else dist[u][0] = dp[up[u][0]] - 2 * f[up[u][0]];
}
FOR(i, 1, 17) {
FOR(u, 1, n) {
dist[u][i] = min(dist[up[u][i - 1]][i - 1], dist[u][i - 1]);
}
}
}
pa ed[N];
ll get(ll u, ll k) {
for(int j = 0; (1 << j) <= k; j++) {
if(bit(k, j)) u = up[u][j];
}
return u;
}
ll lca(ll u, ll v) {
if(h[u] < h[v]) swap(u, v);
u = get(u, h[u] - h[v]);
if(u == v) return u;
FORD(i, 17, 0) {
if(up[v][i] == up[u][i]) {
u = up[u][i];
v = up[v][i];
}
}
return up[u][0];
}
ll distance(ll u, ll v) {
ll p = lca(u, v);
return h[u] + h[v] - 2 * h[p];
}
void hbmt() {
cin >> n >> s >> q >> E;
FOR(i, 1, n - 1) {
ll u, v, w;
cin >> u >> v >> w;
ed[i] = {u, v};
g[u].push_back({v, w});
g[v].push_back({u, w});
}
FOR(i, 1, s) {
ll x;
cin >> x;
dx[x] = 1;
}
dfs(E, 0);
build_dist();
FOR(i, 1, q) {
ll id, r;
cin >> id >> r;
ll u = ed[id].fi, v = ed[id].se;
if(h[u] > h[v]) swap(u, v);
if(distance(E, u) + distance(u, v) + distance(v, r) == distance(E, r)) {
ll k = h[r] - h[v];
ll mn = dp[r] == INF ? INF : dp[r] - 2 * f[r], cur = f[r];
for(int j = 0; (1 << j) <= k; j++) {
if(bit(k, j)) {
mn = min(dist[r][j], mn);
r = up[r][j];
}
}
if(mn == INF) cout << "oo\n";
else cout << mn + cur << '\n';
}
else {
cout << "escaped\n";
}
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
#define NAME "hbmt"
if(fopen(NAME".inp", "r")) {
freopen(NAME".inp", "r", stdin);
freopen(NAME".out", "w", stdout);
}
//int t;cin>>t;while(t--)
hbmt();
return 0;
}
