/*
ID: varunra2
LANG: C++
TASK: valley
*/
#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#include "lib/debug.h"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define debug_arr(...) \
cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__)
#pragma GCC diagnostic ignored "-Wsign-compare"
//#pragma GCC diagnostic ignored "-Wunused-parameter"
//#pragma GCC diagnostic ignored "-Wunused-variable"
#else
#define debug(...) 42
#endif
#define EPS 1e-9
#define IN(A, B, C) assert(B <= A && A <= C)
#define INF (ll)1e15
#define MEM(a, b) memset(a, (b), sizeof(a))
#define MOD 1000000007
#define MP make_pair
#define PB push_back
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define x first
#define y second
const double PI = acos(-1.0);
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> PII;
typedef map<int, int> MPII;
typedef multiset<int> MSETI;
typedef set<int> SETI;
typedef set<string> SETS;
typedef vector<ll> VI;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<string> VS;
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto& a : x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#pragma GCC diagnostic ignored "-Wsign-compare"
// util functions
int n, s, e, q;
vector<VII> adj;
VI tin;
VI tout;
int curtime = 0;
VI magic;
VI dist;
VVI parmq;
VI cmin;
vector<bool> shop;
VII edg;
VVI lca;
const int segsize = 20; // change this when submitting
// e is the root
void init() {
adj.resize(n);
tin.resize(n);
tout.resize(n);
magic.resize(n);
dist.resize(n);
parmq.resize(n);
cmin.resize(n);
shop.resize(n);
edg.resize(n - 1);
lca.resize(n);
for (int i = 0; i < n; i++) {
parmq[i].resize(segsize);
lca[i].resize(segsize);
cmin[i] = INF;
}
}
bool isAnc(int u, int v) {
if (u == -1) return true;
if (v == -1) return false;
return tin[u] <= tin[v] and tout[u] >= tout[v];
}
void dfs_lca(int u, int v) {
lca[u][0] = v;
tin[u] = ++curtime;
for (int i = 1; i < segsize; i++) {
int to = lca[u][i - 1];
if (to == -1)
lca[u][i] = -1;
else
lca[u][i] = lca[to][i - 1];
}
for (auto& x : adj[u]) {
if (x.x == v) continue;
dfs_lca(x.x, u);
}
tout[u] = ++curtime;
}
void dfs_dist(int u, int v) {
for (auto& x : adj[u]) {
if (x.x == v) continue;
dist[x.x] = dist[u] + x.y;
dfs_dist(x.x, u);
}
}
void dfs_magic(int u, int v) {
for (auto& x : adj[u]) {
if (x.x == v) continue;
dfs_magic(x.x, u);
cmin[u] = min(cmin[u], cmin[x.x]);
}
if (shop[u]) cmin[u] = dist[u];
magic[u] = -2 * dist[u] + cmin[u];
}
void dfs_build_parmq(int u, int v) {
parmq[u][0] = magic[u];
for (int i = 1; i < segsize; i++) {
int to = lca[u][i - 1];
if (to == -1)
parmq[u][i] = parmq[u][i - 1];
else
parmq[u][i] = min(parmq[u][i - 1], parmq[to][i - 1]);
}
for (auto& x : adj[u]) {
if (x.x == v) continue;
dfs_build_parmq(x.x, u);
}
}
ll qry(int u, int v) {
ll ret = INF;
for (int i = segsize - 1; i >= 0; i--) {
if (!isAnc(lca[u][i], v)) {
ret = min(ret, parmq[u][i]);
u = lca[u][i];
}
}
ret = min(ret, min(magic[v], magic[u]));
return ret;
}
int main() {
#ifndef ONLINE_JUDGE
freopen("valley.in", "r", stdin);
freopen("valley.out", "w", stdout);
#endif
cin.sync_with_stdio(0);
cin.tie(0);
cin >> n >> s >> q >> e;
e--;
init();
for (int i = 0; i < n - 1; i++) {
int u, v, w;
cin >> u >> v >> w;
u--;
v--;
adj[u].PB(MP(v, w));
adj[v].PB(MP(u, w));
edg[i] = MP(u, v);
}
for (int i = 0; i < s; i++) {
int c;
cin >> c;
c--;
shop[c] = true;
}
dfs_lca(e, -1); // got in and out times of each node
dfs_dist(e, -1); // got distances
dfs_magic(e, -1); // made the magic array
// now we need to calculate
dfs_build_parmq(e, -1);
// for(int i = 0; i < q; i++) {
// }
for (int i = 0; i < q; i++) {
int ind, r;
cin >> ind >> r;
ind--;
r--;
int u, v;
u = edg[ind].x;
v = edg[ind].y;
if (dist[u] < dist[v]) swap(u, v);
if (!isAnc(u, r)) {
cout << "escaped\n";
} else {
ll ret = dist[r] + qry(r, u);
if (shop[r]) ret = 0;
if (ret <= INF / 10 + 1ll)
cout << ret << '\n';
else
cout << "oo" << '\n';
}
}
return 0;
}
