/**
____ ____ ____ ____ ____
||a |||t |||o |||d |||o ||
||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|
**/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N_MAX = 100000;
const int BITS = 17;
const ll INF = LLONG_MAX / 2;
int N, S, Q, E;
bool shop[N_MAX + 2];
struct Edge {
int u, v;
int len;
int to (int x) {
return u ^ v ^ x;
}
};
Edge edges[N_MAX + 2];
vector <int> adj[N_MAX + 2];
int pedge[N_MAX + 2];
int level[N_MAX + 2];
ll depth[N_MAX + 2];
ll minDown[N_MAX + 2];
void dfs (int u) {
if (shop[u] == true) {
minDown[u] = 0;
} else {
minDown[u] = INF;
}
for (int e : adj[u]) {
int v = edges[e].to(u);
if (v != edges[pedge[u]].to(u)) {
pedge[v] = e;
level[v] = level[u] + 1;
depth[v] = depth[u] + edges[e].len;
dfs(v);
minDown[u] = min(minDown[u], minDown[v] + edges[e].len);
}
}
}
int ancestor[N_MAX + 2][BITS];
ll minPath[N_MAX + 2][BITS];
void precalc () {
minDown[0] = INF;
for (int k = 0; k < BITS; k++) {
minPath[0][k] = INF;
}
for (int u = 1; u <= N; u++) {
int v = edges[pedge[u]].to(u);
ancestor[u][0] = v;
if (minDown[u] == INF) {
minPath[u][0] = INF;
} else {
minPath[u][0] = minDown[u] - depth[u];
}
if (minDown[v] != INF) {
minPath[u][0] = min(minPath[u][0], minDown[v] - depth[v]);
}
}
for (int k = 1; k < BITS; k++) {
for (int u = 1; u <= N; u++) {
ancestor[u][k] = ancestor[ancestor[u][k - 1]][k - 1];
minPath[u][k] = min(minPath[u][k - 1], minPath[ancestor[u][k - 1]][k - 1]);
}
}
}
pair <int, ll> goUp (int u, int len) {
ll mn = minDown[u];
for (int k = 0; k < BITS; k++) {
if ((len >> k) & 1) {
mn = min(mn, minPath[u][k]);
u = ancestor[u][k];
}
}
return make_pair(u, mn);
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> N >> S >> Q >> E;
for (int e = 1; e <= N - 1; e++) {
cin >> edges[e].u >> edges[e].v >> edges[e].len;
adj[edges[e].u].push_back(e);
adj[edges[e].v].push_back(e);
}
for (int i = 1; i <= S; i++) {
int u;
cin >> u;
shop[u] = true;
}
dfs(E);
precalc();
for (int i = 1; i <= Q; i++) {
int e, u;
cin >> e >> u;
int v = edges[e].u;
if (level[v] < level[edges[e].v]) {
v = edges[e].v;
}
if (level[v] > level[u]) {
cout << "escaped\n";
continue;
}
int x; ll mn;
tie(x, mn) = goUp(u, level[u] - level[v]);
if (x != v) {
cout << "escaped\n";
continue;
}
if (mn == INF) {
cout << "oo\n";
} else {
cout << depth[u] + mn << "\n";
}
}
return 0;
}
