#include <bits/stdc++.h>
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define fast ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
#define all(v) v.begin(),v.end()
#define pb push_back
#define sz size()
#define ft first
#define sd second
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef unsigned long long ull;
const int N = 1e6 + 5;
const ll M = 1e8;
const ll inf = 1e18;
const ll mod = 1e9;
const double Pi = acos(-1);
ll binpow(ll x, ll ti) { ll res = 1;while (ti){if(ti & 1)res *= x;x *= x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll binmul(ll x, ll ti) { ll res = 0;while (ti){if(ti & 1)res += x;x += x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll nok(ll a, ll b) { return (a*b)/__gcd(abs(a),abs(b)) * (a*b > 0 ? 1 : -1); }
bool odd(ll n) { return (n % 2 == 1); }
bool even(ll n) { return (n % 2 == 0); }
ll n, s, k, e, dp[N], in[N], out[N], timer, up[N][30], mnn[N][30], sel[N], h[N], d[N];
pll edge[N];
vector <pll> g[N];
void dfs(ll v, ll pr) {
up[v][0] = pr;
in[v] = ++ timer;
ll mn = inf;
for (auto [to, w] : g[v]) {
if (to != pr) {
h[to] = h[v] + 1;
d[to] = d[v] + w;
dfs(to, v);
mn = min(mn, dp[to] + w);
}
}
if (sel[v]) mn = 0;
dp[v] = mn;
for (auto [to, w] : g[v]) {
if (to != pr) {
mnn[to][0] = dp[v] - d[v];
}
}
out[v] = ++ timer;
}
ll get(ll u, ll v, ll pr) {
if (in[v] >= in[pr] && out[v] <= out[pr]);
else return inf;
ll mn = dp[v] + (d[u] - d[v]);
for (int i = 0; i <= 25; ++ i) {
ll cur = up[v][i];
//cout << cur << " " << pr << "\n";
if (in[cur] >= in[pr] && out[cur] <= out[pr]) {
mn = min(mn, mnn[v][i] + d[u]);
} else {
mn = min(mn, get(u, up[v][i - 1], pr));
break;
}
}
return mn;
}
const void solve(/*Armashka*/) {
cin >> n >> s >> k >> e;
for (int i = 1; i < n; ++ i) {
ll u, v, w;
cin >> u >> v >> w;
g[u].pb({v, w});
g[v].pb({u, w});
edge[i] = {u, v};
}
for (int i = 1; i <= n; ++ i) dp[i] = inf;
for (int i = 1; i <= s; ++ i) {
ll x; cin >> x;
sel[x] = 1;
}
dfs(e, -1);
//for (int i = 1; i <= n; cout << dp[i] << " ", ++ i);
for (int i = 1; i <= 25; ++ i) {
for (int j = 1; j <= n; ++ j) {
up[j][i] = up[up[j][i - 1]][i - 1];
mnn[j][i] = min(mnn[j][i - 1], mnn[up[j][i - 1]][i - 1]);
}
}
for (int i = 1; i <= k; ++ i) {
ll id, start;
cin >> id >> start;
ll a = edge[id].ft, b = edge[id].sd;
if (h[a] < h[b]) swap(a, b);
if (in[a] > in[start] || out[a] < out[start]) {
cout << "escaped\n";
continue;
}
ll res = get(start, start, a);
if (res == inf) cout << "oo\n";
else cout << res << "\n";
}
}
signed main() {
fast;
//freopen("divide.in", "r", stdin);
//freopen("divide.out", "w", stdout);
int tt = 1;
//cin >> tt;
while (tt --) {
solve();
}
}
/*
5 4 4
1 2
3 1
3 4
5 3
4 5 2 3
2 1 3 1
1 3 5
2 3 4 5
2 1 3 1
*/
