#include <bits/stdc++.h>
using namespace std;
typedef pair<long long,long long> ii;
static vector<ii> adj[100005];
static long long dis[100005];
static long long depth[100005];
static long long vis[100005];
static long long sz[100005];
static long long cented[100005];
static vector<ii> parent[100005];
static vector<long long> nodes;
static vector<ii> disc[100005];
static vector<int> disc2[100005];
static long long low[100005];
static long long high[100005];
int cnt = 0;
long long n, q, S, E;
void dfs(int u){
sz[u] = 1;
nodes.push_back(u);
for(ii v : adj[u]){
if(sz[v.first] == 0 && !cented[v.first]){
dis[v.first] = dis[u] + v.second;
dfs(v.first);
sz[u] += sz[v.first];
}
}
}
void dfs2(int u){
low[u] = cnt;
high[u] = cnt;
cnt++;
vis[u] = true;
for(ii v : adj[u]){
if(!vis[v.first]){
depth[v.first] = depth[u] + 1;
dfs2(v.first);
high[u] = max(high[u],high[v.first]);
}
}
}
void recurse(int r, int p){
nodes.clear();
dfs(r);
int centroid;
for(int u : nodes){
long long big = sz[r] - sz[u];
for(ii v : adj[u]){
if(!cented[v.first] && sz[v.first] < sz[u]){
big = max(big, sz[v.first]);
}
}
if(2*big <= sz[r]){
centroid = u;
break;
}
}
for(int u : nodes){
sz[u] = 0;
if(p != -1) parent[u].push_back(ii(p,dis[u]));
dis[u] = 0;
}
cented[centroid] = true;
for(ii v : adj[centroid]){
dis[v.first] = v.second;
if(!cented[v.first]) recurse(v.first, centroid);
}
}
struct edge{
long long u;
long long v;
long long w;
};
class SegmentTree{
public:
int nn;
vector<long long> tree;
void create(int nnn){
nn = nnn;
for(int i = 0;i < 2*nn+4;i++){
tree.push_back(10234567890123456);
}
}
void update(int i, long long v){
i += nn;
while(i > 0){
tree[i] = min(tree[i], v);
i >>= 1;
}
}
long long query(int l, int r){
long long res = 10234567890123456;
for(l += nn, r += nn;l < r;l >>= 1, r >>= 1){
if(l&1){
res = min(res, tree[l]);
l++;
}
if(r&1){
r--;
res = min(res,tree[r]);
}
}
return res;
}
};
static SegmentTree seg[100005];
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> S >> q >> E;
E--;
edge edges[n-1];
for(int i = 0;i < n-1;i++){
int a, b, c;
cin >> a >> b >> c;
a--; b--;
adj[a].push_back(ii(b,c));
adj[b].push_back(ii(a,c));
edges[i] = {a,b,c};
}
recurse(0,-1);
dfs2(0);
for(int i = 0;i < n;i++){
parent[i].push_back(ii(i,0));
}
for(int i = 0;i < S;i++){
int x;
cin >> x;
x--;
int preorder = low[x];
for(ii p : parent[x]){
disc[p.first].push_back(ii(preorder,p.second));
}
}
for(int i = 0;i < n;i++){
sort(disc[i].begin(),disc[i].end());
seg[i].create((int)disc[i].size());
for(int j = 0;j < disc[i].size();j++){
ii x = disc[i][j];
disc2[i].push_back(x.first);
seg[i].update(j, x.second);
}
}
while(q--){
int C, R;
cin >> C >> R;
C--; R--;
int subtree;
int X = edges[C].u;
int Y = edges[C].v;
if(depth[X] > depth[Y]){
subtree = X;
}
else{
subtree = Y;
}
int LOW = low[subtree];
int HIGH = high[subtree];
bool isRin = (LOW <= low[R] && low[R] <= HIGH);
bool isEin = (LOW <= low[E] && low[E] <= HIGH);
if(isRin == isEin){
cout << "escaped\n";
continue;
}
long long ans = 10234567890123456;
for(ii P : parent[R]){
long long res = 10234567890123456;
int p = P.first;
bool isPin = (LOW <= low[p] && low[p] <= HIGH);
if(isPin != isRin){
continue;
}
int lEnd = lower_bound(disc2[p].begin(),disc2[p].end(), LOW) - disc2[p].begin();
int rEnd = upper_bound(disc2[p].begin(),disc2[p].end(), HIGH) - disc2[p].begin() - 1;
if(isRin){
res = min(res, seg[p].query(lEnd,rEnd+1));
}
else{
res = min(res, seg[p].query(0,lEnd));
res = min(res, seg[p].query(rEnd+1,(int)disc2[p].size()));
}
ans = min(ans, res + P.second);
}
if(ans > 10234527890123450)
cout << "oo\n";
else cout << ans << "\n";
}
}
