#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using piii = array<int, 3>;
#define pb push_back
const int LG = 18 + 2, N = 1e5 + 4;
const ll D = 1e15, INF = 1ll << 62;
struct Info {
int anc;
ll cost;
Info () {
anc = -1, cost = INF;
}
} info[N][LG];
int n, s, q, e, down[N], h[N];
ll mnd[N], d[N];
bool shop[N];
vector<piii> g[N];
void dfs(int v = e) {
if (v != e) {
for (int i = 1; i < LG; i++) {
int u = info[v][i - 1].anc;
if (u != -1)
info[v][i].anc = info[u][i - 1].anc;
}
}
for (auto [u, w, idx] : g[v]) {
if (u != info[v][0].anc) {
d[u] = d[v] + w;
h[u] = h[v] + 1;
down[idx] = u;
info[u][0].anc = v;
dfs(u);
mnd[v] = min(mnd[v], mnd[u]);
}
}
if (shop[v])
mnd[v] = d[v];
}
void calcCost(int v = e) {
info[v][0].cost = mnd[v] - (d[v] << 1);
for (int i = 1; i < LG; i++) {
int u = info[v][i - 1].anc;
ll tmp = info[v][i - 1].cost;
if (u != -1)
tmp = min(tmp, info[u][i - 1].cost);
info[v][i].cost = tmp;
}
for (auto [u, w, idx] : g[v])
if (u != info[v][0].anc)
calcCost(u);
}
int up(int v, int cnt) {
for (int i = 0; i < LG; i++)
if (((1 << i) & cnt) && v != -1)
v = info[v][i].anc;
return v;
}
ll getMin(int v, int cnt) {
ll ret = INF;
for (int i = 0; i < LG; i++) {
if (((1 << i) & cnt) && v != -1) {
ret = min(ret, info[v][i].cost);
v = info[v][i].anc;
}
}
return ret;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> s >> q >> e;
for (int i = 0; i < n - 1; i++) {
int v, u, w;
cin >> v >> u >> w;
v--, u--;
g[v].pb({u, w, i});
g[u].pb({v, w, i});
}
for (int i = 0; i < s; i++) {
int v;
cin >> v;
v--;
shop[v] = 1;
}
for (int i = 0; i < n; i++)
mnd[i] = INF;
e--;
dfs();
calcCost();
while (q--) {
int edge, v;
cin >> edge >> v;
edge--, v--;
int u = down[edge];
int difh = h[v] - h[u];
if (difh < 0 || up(v, difh) != u)
cout << "escaped";
else {
ll ans = getMin(v, difh + 1) + d[v];
if (ans > D)
cout << "oo";
else
cout << ans;
}
cout << '\n';
}
return 0;
}
