//Huyduocdithitp
#include <bits/stdc++.h>
#define int long long
typedef long long ll;
#define endl '\n'
#define yes cout<<"YES"<<endl;
#define no cout<<"NO"<<endl;
#define fi first
#define se second
#define pii pair<ll, ll>
#define inf 1e18
#define faster ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MP make_pair
#define TASK "ghuy4g"
#define start if(fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin);freopen(TASK".out","w",stdout);}
#define LOG 19
#define N 100005
using namespace std;
struct Edge {
ll u, v, w;
} canh[N]; // u la con cua v
ll n, s, q, e, high[N], dep[N], par[N][LOG + 2], spe[N], spe1[N][LOG + 2];
ll in[N], out[N], timeDfs;
vector<pii> adj[N];
void dfs(ll u, ll parent) {
in[u] = ++ timeDfs;
for (auto v : adj[u]) {
if (v.fi == parent) continue;
par[v.fi][0] = u;
high[v.fi] = high[u] + 1;
dep[v.fi] = dep[u] + v.se;
dfs(v.fi, u);
}
out[u] = timeDfs;
}
bool is_an(ll u, ll v) { // u co phai to tien cua v khong
return in[u] <= in[v] && in[v] <= out[u];
}
void prepare() {
for (int j = 1; j <= LOG; j ++) {
for (int i = 1; i <= n; i ++) {
ll p = par[i][j - 1];
par[i][j] = par[p][j - 1];
spe1[i][j] = min(spe1[i][j - 1], spe1[p][j - 1]);
}
}
}
ll kth_par(ll u, ll k) {
for (int j = LOG; j >= 0; j --) {
if (k >= (1 << j)) {
k -= (1 << j);
u = par[u][j];
}
}
return u;
}
ll get1(ll u, ll k) {
k ++ ;
ll res = inf;
for (int j = LOG; j >= 0; j --) {
if (k >= (1 << j)) {
k -= (1 << j);
//cout << u << " " << k << " " << j << endl;
res = min(res, spe1[u][j]);
u = par[u][j];
}
}
return res;
}
ll lca(ll u, ll v) {
if (high[u] > high[v]) swap(u, v);
for (int j = LOG; j >= 0; j --) {
if ((1 << j) <= high[v] - high[u]) {
v = par[v][j];
}
}
if (u == v) return u;
for (int j = LOG; j >= 0; j --) {
if (par[v][j] != par[u][j]) {
u = par[u][j];
v = par[v][j];
}
}
return par[u][0];
}
void dfs1(ll u, ll parent) {
if (spe[u] == -1) spe[u] = inf;
else spe[u] = dep[u];
for (auto v : adj[u]) {
if (v.fi == parent) continue;
dfs1(v.fi, u);
spe[u] = min(spe[u], spe[v.fi]);
}
spe1[u][0] = spe[u] - 2 * dep[u];
}
ll solve2(ll u, ll R) {
ll res = inf;
res = min(res, spe[R] - dep[R]);
res = min(res, get1(R, high[R] - high[u]) + dep[R]);
return res;
}
void solve(ll I, ll R) {
ll u = canh[I].u;
//cout << I << " " << u << " " << R << " " << is_an(u, R) << endl;
if (is_an(u, R) == 0) {
cout << "escaped" << endl;
return;
}
//cout << "chua thoat" << endl;
ll res = solve2(u, R);
if (res > 1e14) {
cout << "oo" << endl;
}
else {
cout << res << endl;
}
}
signed main(void) {
faster;
cin >> n >> s >> q >> e;
for (int i = 1; i <= n - 1; i ++) {
ll u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
canh[i] = {u, v, w};
spe[i] = -1; spe[i + 1] = -1;
}
dfs(e, e);
for (int i = 1; i <= s; i ++) {
ll u; cin >> u; spe[u] = dep[u];
}
dfs1(e, e);
for (int i = 1; i <= n - 1; i ++) {
if (canh[i].u == par[canh[i].v][0]) {
swap(canh[i].u, canh[i].v); // u luon la con cua v
}
}
//cout << "debug: " << is_an(3, 2) << endl;
prepare();
for (int i = 1; i <= q; i ++) {
ll I, R;
cin >> I >> R;
solve(I, R);
}
return 0;
}
