#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
ll res[100005];
vector <pair <int, int>> graf[100005];
ll depth[100005];
pair <int, int> niz[100005];
int e;
const ll INF = 10000000000000000LL;
struct segment{
ll lazy, res;
} seg[400005];
int tajm;
int in[100005];
int out[100005];
bool jeste[100005];
vector <pair <int, int>> kv[100005];
int n;
void init(int node, int l, int r){
if(l == r){
if(niz[l].second == 1) seg[node].res = niz[l].first;
else seg[node].res = INF;
return;
}
int mid = (l+r)/2;
init(node*2, l, mid);
init(node*2+1, mid+1, r);
seg[node].res = min(seg[node*2].res, seg[node*2+1].res);
}
void dfs1(int v, int parent, int kolko){
depth[v] = depth[parent] + kolko;
in[v] = ++tajm;
niz[in[v]] = {depth[v], jeste[v]};
for(auto c : graf[v]){
if(c.first == parent) continue;
dfs1(c.first, v, c.second);
}
out[v] = tajm;
}
void propagate(int node, int l, int r){
seg[node].res += seg[node].lazy;
if(l == r){
seg[node].lazy = 0;
return;
}
seg[node*2].lazy += seg[node].lazy;
seg[node*2+1].lazy += seg[node].lazy;
seg[node].lazy = 0;
}
void upd(int node, int l, int r, int tl, int tr, int val){
if(tl > tr) return;
propagate(node, l, r);
if(tl > r || l > tr) return;
if(tl <= l && r <= tr){
seg[node].lazy += val;
propagate(node, l, r);
return;
}
int mid = (l+r)/2;
upd(node*2, l, mid, tl, tr, val);
upd(node*2+1, mid+1, r, tl, tr, val);
seg[node].res = min(seg[node*2].res, seg[node*2+1].res);
}
ll query(int node, int l, int r, int tl, int tr){
if(tl > tr) return INF;
propagate(node, l, r);
if(tl > r || l > tr) return INF;
if(tl <= l && r <= tr) return seg[node].res;
int mid = (l+r)/2;
return min(query(node*2, l, mid, tl, tr), query(node*2+1, mid+1, r, tl, tr));
}
struct edge{
int a, b, c;
} grana[100005];
bool is_parent(int a, int b){
return in[a] <= in[b] && out[b] <= out[a];
}
void dfs(int v, int parent, int kolko){
upd(1, 1, n, 1, n, kolko);
upd(1, 1, n, in[v], out[v], -2*kolko);
for(auto c : kv[v]){
int edg = c.first;
if(in[grana[edg].a] > in[grana[edg].b]) swap(grana[edg].a, grana[edg].b);
int b = grana[edg].b;
if(is_parent(b, v)) res[c.second] = query(1, 1, n, in[b], out[b]);
else res[c.second] = min(query(1, 1, n, 1, in[b]-1), query(1, 1, n, out[b]+1, n));
}
for(auto c : graf[v]){
if(c.first == parent) continue;
dfs(c.first, v, c.second);
}
upd(1, 1, n, 1, n, -kolko);
upd(1, 1, n, in[v], out[v], 2*kolko);
}
bool check(int x, int edg){
if(in[grana[edg].a] > in[grana[edg].b]) swap(grana[edg].a, grana[edg].b);
int b = grana[edg].b;
if(is_parent(b, e)) return is_parent(b, x);
else return !is_parent(b, x);
}
int main(){
ios_base::sync_with_stdio(false), cin.tie(0);
cout.precision(10);
cout << fixed;
int s, q;
cin >> n >> s >> q >> e;
for(int i=1; i<n; i++){
int a, b, c;
cin >> a >> b >> c;
graf[a].push_back({b, c});
graf[b].push_back({a, c});
grana[i] = {a, b, c};
}
for(int j=1; j<=s; j++){
int x;
cin >> x;
jeste[x] = 1;
}
dfs1(1, 0, 0);
init(1, 1, n);
for(int j=1; j<=q; j++){
int a, b;
cin >> b >> a;
if(check(a, b)){
res[j] = -1;
continue;
}
res[j] = INF;
kv[a].push_back({b, j});
}
dfs(1, 0, 0);
for(int j=1; j<=q; j++){
if(res[j] == -1) cout << "escaped\n";
else if(res[j] > INF/10) cout << "oo\n";
else cout << res[j] << "\n";
}
return 0;
}
