// In the name of God
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define mp make_pair
typedef long long ll;
#define int ll
const int N = 1e5 + 5, MOD = 1e9 + 7, L = 22, inf = 1e18;
int n, s, q, E;
vector<pair<int, int> > adj[N];
bool shop[N];
pair<int, int> edge[N];
int h[N], up[N][L], tin[N], tout[N], T;
ll dis[N], dpDown[N], mn2[N], dpUp[N];
ll up2[2][N][L];
int mn[N];
bool anc(int v, int u) {
return tin[v] <= tin[u] && tout[v] >= tin[u];
}
int lca(int v, int u) {
if (tin[v] < tin[u])
swap(v, u);
if (anc(v, u))
return v;
for (int l = L - 1; l >= 0; l--) {
if (!anc(up[v][l], u))
v = up[v][l];
}
return up[v][0];
}
ll DIS(int v, int u) {
if (v == 0 || u == 0)
return inf;
return dis[v] + dis[u] - 2 * dis[lca(v, u)];
}
void dfs(int v, int p) {
tin[v] = ++T;
up[v][0] = p;
for (int l = 1; l < L; l++)
up[v][l] = up[up[v][l - 1]][l - 1];
dpDown[v] = 0;
if (shop[v]) {
dpDown[v] = v;
}
for (auto [u, w] : adj[v]) {
if (u == p)
continue;
dis[u] = dis[v] + w;
h[u] = h[v] + 1;
dfs(u, v);
if (DIS(dpDown[u], v) < DIS(dpDown[v], v))
dpDown[v] = dpDown[u];
}
tout[v] = ++T;
}
void dfs2(int v, int p) {
up2[0][v][0] = mn2[p] - dis[p];
up2[1][v][0] = mn2[p] + dis[p];
for (int l = 1; l < L; l++) {
up2[0][v][l] = min(up2[0][v][l - 1], up2[0][up[v][l - 1]][l - 1]);
up2[1][v][l] = min(up2[1][v][l - 1], up2[1][up[v][l - 1]][l - 1]);
}
mn[v] = dpDown[v];
mn2[v] = inf;
if (DIS(dpDown[v], v) > DIS(dpUp[v], v))
mn[v] = dpUp[v];
for (auto [u, w] : adj[v]) {
if (u == p)
continue;
if (mn[v] != dpDown[u]) {
mn2[v] = min(mn2[v], DIS(dpDown[u], v));
}
}
if (mn[v] != dpUp[v]) {
mn2[v] = min(mn2[v], DIS(dpUp[v], v));
}
int tmp1 = 0, tmp2 = 0;
for (auto [u, w] : adj[v]) {
if (u == p)
continue;
if (DIS(tmp1, v) > DIS(dpDown[u], v))
tmp2 = tmp1, tmp1 = dpDown[u];
else if (DIS(tmp2, v) > DIS(dpDown[u], v))
tmp2 = dpDown[u];
}
if (DIS(dpUp[v], v) < DIS(tmp1, v))
tmp2 = tmp1, tmp1 = dpUp[v];
else if (DIS(dpUp[v], v) < DIS(tmp2, v))
tmp2 = dpUp[v];
if (shop[v]) {
tmp1 = v;
}
for (auto [u, w] : adj[v]) {
if (u == p)
continue;
if (tmp1 != dpDown[u]) {
dpUp[u] = tmp1;
}
else
dpUp[u] = tmp2;
dfs2(u, v);
}
}
bool in_path(int v, int u, int x, int y) {
if (tin[x] > tin[y])
swap(x, y);
int l = lca(v, u);
return anc(l, x) && (anc(y, v) || anc(y, u));
}
ll minUp(int t, int v, int len) {
ll ans = inf;
for (int i = 0; i < L; i++) {
if (len & (1 << i)) {
ans = min(ans, up2[t][v][i]);
v = up[v][i];
}
}
return ans;
}
void solve() {
cin >> n >> s >> q >> E;
for (int i = 0; i < n - 1; i++) {
int v, u, w; cin >> v >> u >> w;
adj[v].pb(mp(u, w));
adj[u].pb(mp(v, w));
edge[i] = mp(v, u);
}
int r = 1;
for (int i = 0; i < s; i++) {
int v; cin >> v;
shop[v] = true;
}
dfs(r, 0);
tout[0] = 1e9;
mn2[0] = inf;
for (int i = 0; i < L; i++)
up2[0][0][i] = up2[1][0][i] = inf;
dfs2(r, 0);
while (q--) {
int i, v; cin >> i >> v;
--i;
int x = edge[i].fi, y = edge[i].se;
if (tin[x] > tin[y])
swap(x, y);
int l = lca(v, E);
if (!in_path(v, E, x, y)) {
cout << "escaped\n";
continue;
}
l = lca(v, mn[v]);
if (!in_path(v, mn[v], x, y)) {
cout << DIS(v, mn[v]) << '\n';
continue;
}
int u = mn[v];
if (v == l) {
ll val = min(mn2[x] + dis[x], minUp(1, x, h[x] - h[v]));
if (val <= 1e17) {
cout << val - dis[v] << '\n';
continue;
}
}
else if (in_path(l, v, x, y)) {
ll val = min(mn2[v] - dis[v], minUp(0, v, h[v] - h[y]));
if (val <= 1e17) {
cout << val + dis[v] << '\n';
continue;
}
}
else {
ll val1 = min(mn2[v] - dis[v], minUp(0, v, h[v] - h[l])) + dis[v];
ll val2 = min(mn2[x] + dis[x], minUp(1, x, h[x] - h[l])) - dis[l] + dis[v] - dis[l];
if (min(val1, val2) <= 1e17) {
cout << min(val1, val2) << '\n';
continue;
}
}
cout << "oo" << '\n';
}
}
int32_t main() {
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
solve();
return 0;
}
