/*
ID: USACO_template
LANG: C++
PROG: USACO
*/
#include <iostream> //cin , cout
#include <fstream> //fin, fout
#include <stdio.h> // scanf , pringf
#include <cstdio>
#include <algorithm> // sort , stuff
#include <stack> // stacks
#include <queue> // queues
#include <map>
#include <string>
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi; /// adjlist without weight
typedef vector<pii> vii; /// adjlist with weight
typedef vector<pair<int,pii>> vpip; /// edge with weight
typedef long long ll;
#define mp make_pair
#define fst first
#define snd second
#define pb push_back
#define sz(x) (int)(x).size()
#define trav(u, adj_v) for (auto& u: adj_v)
const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5; //
const ll INF = 1e18; //
#define MAXV 100007
#define MAXE 100007
/// code from USACO examples
void setIO(string name) {
ios_base::sync_with_stdio(0); cin.tie(0);
freopen((name+".in").c_str(),"r",stdin);
freopen((name+".out").c_str(),"w",stdout);
}
bool debug = false, submit = true;
int N, S, Q, E;
vii adj[MAXV];
pii edge[MAXV];
int isShop[MAXV];
#define MAXLCALOG 20
int p[MAXV], depth[MAXV], anc[MAXV][MAXLCALOG];
ll dist[MAXV], dp[MAXV], dpanc[MAXV][MAXLCALOG];
void buildTree(int v_s) {
depth[v_s] = 0; p[v_s] = 0; dist[v_s] = 0LL;
queue<int> q;
q.push(v_s);
while(!q.empty()) {
int curr = q.front();
q.pop();
for(int i = 0; i < adj[curr].size(); i++) {
int u = adj[curr][i].fst;
if (u == p[curr]) continue;
p[u] = curr;
depth[u] = 1 + depth[curr];
dist[u] = dist[curr] + adj[curr][i].snd;
q.push(u);
}
}
}
void prepLCA() {
for(int i = 1; i <= N; i++) anc[i][0] = p[i];
for(int j = 1; j < MAXLCALOG; j++)
for(int i = 1; i <= N; i++)
anc[i][j] = anc[anc[i][j-1]][j-1];
}
int upD(int curr, int dist) {
if(dist == 0) return curr;
for(int k = MAXLCALOG - 1; k>=0; k--) {
while(dist >= (1<<k) ) {
curr = anc[curr][k];
dist -= (1<<k);
}
if(dist == 0) return curr;
}
return curr;
}
int getP(int curr, int wantedD) {
for(int k = MAXLCALOG - 1; depth[curr] != wantedD; k--) {
while(depth[curr] - (1<<k) >= wantedD) {
curr = anc[curr][k];
}
}
return curr;
}
bool canEscape(int b, int s) {
if(depth[s] < depth[b]) return true;
if(depth[s] == depth[b]) return (s!=b);
/// now s is deeper than b
int dist = depth[s] - depth[b];
if(upD(s, dist) == b) return false;
return true;
}
ll dfsDP(int v) {
if(v != E && sz(adj[v]) == 1) {
// leaf
if (isShop[v]) {
dp[v] = dist[v] - dist[v] * 2LL;
return dist[v];
} else {
dp[v] = INF;
return INF;
}
}
ll minShopDist = INF;
if(isShop[v]) minShopDist = dist[v];
dp[v] = INF;
for(int i = 0; i < sz(adj[v]); i++) {
int u = adj[v][i].fst;
if (u == p[v]) continue;
ll d0 = dfsDP(u);
minShopDist = min(minShopDist, d0);
}
if(minShopDist!= INF) dp[v] = minShopDist - dist[v] * 2LL;
return minShopDist;
}
void prepDPjump() {
for(int i = 1; i <= N; i++) dpanc[i][0] = min(dp[i], dp[anc[i][0]]);
for(int j = 1; j < MAXLCALOG; j++)
for(int i = 1; i <= N; i++)
dpanc[i][j] = min(dpanc[i][j-1], dpanc[anc[i][j-1]][j-1]);
}
ll dpUpD(int curr, int dist) {
if(dist == 0) return dp[curr];
ll ans0 = INF;
for(int k = MAXLCALOG - 1; k>=0; k--) {
while(dist >= (1<<k) ) {
ans0 = min(ans0, dpanc[curr][k]);
curr = anc[curr][k];
dist -= (1<<k);
}
if(dist == 0) return min(ans0, dp[curr]);
}
return min(ans0, dp[curr]);
}
int main() {
debug = true; submit = false;
if(submit) setIO("testName");
int i, j, k;
cin >> N >> S >> Q >> E;
for(i=1;i<=N-1;i++) {
int a, b, w; cin >> a >> b >> w;
adj[a].pb(mp(b,w)); adj[b].pb(mp(a, w));
edge[i] = mp(a, b);
}
buildTree(E); prepLCA();
for(i=0; i<S; i++) {
int a; cin >> a;
isShop[a] = 1;
}
dfsDP(E);
prepDPjump();
for(i = 0; i<Q; i++) {
int ei, src; cin >> ei >> src;
int a = edge[ei].fst, b = edge[ei].snd;
if(depth[a] > depth[b]) swap(a, b);
if(canEscape(b, src)) {
cout << "escaped" << endl;
} else {
int d0 = depth[src] - depth[b];
ll ans = dpUpD(src, d0);
if(ans == INF) cout << "oo" << endl;
else cout << dist[src] + ans << endl;
}
}
}
