#include <bits/stdc++.h>
typedef long long int ll;
#define INF (ll)(1e15 + 7)
#define INF2 998244353ll
#define N (ll)(1e5 + 5)
using namespace std;
#define int ll
#define lsb(x) (x & (-x))
int n, s, q, e, g, h, t;
int d[N], depth[N];
array<int, 3> edges[N];
vector<pair<int, int>> v[N];
bool shop[N];
int dp1[N];
int dp2[N];
int par[N][20];
int cur = 1;
int st[N], en[N], ans[N];
vector<pair<int ,int>> z[N];
struct segTree{
int n;
vector<int> tree, minn;
segTree(int _n){
n = _n + 1;
while(n != lsb(n))n += lsb(n);
tree.resize(2 * n, INF);
minn.resize(2 * n, INF);
}
void push(int i){
if(minn[i] == INF)return;
minn[i * 2] = min(minn[i], minn[i * 2]);
minn[i * 2 + 1] = min(minn[i], minn[i * 2 + 1]);
tree[i * 2] = min(minn[i], tree[i * 2]);
tree[i * 2 + 1] = min(minn[i], tree[i * 2 + 1]);
minn[i] = INF;
}
void update(int ql, int qr, int val){if(val >= INF)return; update(1, 0, n - 1, ql, qr, val);}
void update(int i, int lb, int rb, int ql, int qr, int val){
if(ql > rb || qr < lb)return;
if(ql <= lb && rb <= qr){
minn[i] = min(minn[i], val);
tree[i] = min(tree[i], val);
return;
}
int mid = (lb + rb) / 2;
push(i);
update(i * 2, lb, mid ,ql, qr, val);
update(i * 2 + 1, mid + 1, rb ,ql, qr, val);
tree[i] = min(tree[i * 2], tree[i * 2 + 1]);
}
int calc(int ql, int qr){return calc(1, 0, n - 1, ql, qr);}
int calc(int i, int lb, int rb, int ql, int qr){
if(ql > rb || qr < lb)return INF;
if(ql <= lb && rb <= qr){
return tree[i];
}
int mid = (lb + rb) / 2;
push(i);
return min(calc(i * 2, lb, mid, ql, qr), calc(i * 2 + 1, mid + 1, rb, ql, qr));
}
};
bool isanc(int x, int y){
return (st[y] <= st[x] && en[y] >= en[x]);
}
segTree ss(N * 2);
void dfs(int x ,int p){
par[x][0] = p;
st[x] = cur++;
for(auto u : v[x]){
if(u.first != p){
d[u.first] = d[x] + u.second;
depth[u.first] = depth[x] + 1;
dfs(u.first, x);
dp1[x] = min(dp1[x], dp1[u.first] + u.second);
}
}
en[x] = cur++;
}
void dfs2(int x, int p){
int min1 = INF, min2 = INF;
for(auto u : v[x]){
if(u.first != p){
dfs2(u.first, x);
}
}
for(auto u : v[x]){
if(u.first != p){
g = dp1[u.first] + u.second;
if(g <= min1){
min2 = min1;
min1 = g;
}
else if(g < min2){
min2 = g;
}
}
}
if(shop[x])min1 = min2 = 0;
for(auto u : v[x]){
if(u.first != p){
g = dp1[u.first] + u.second;
if(g == min1){
ss.update(st[u.first], en[u.first], min2 - d[x]);
}
else{
ss.update(st[u.first], en[u.first], min1 - d[x]);
}
}
}
for(auto u : z[x]){
ans[u.second] = min(ans[u.second], d[u.first] + ss.calc(st[u.first], st[u.first]));
}
}
void solve(){
cin >> n >> s >> q >> e;
for(int i=1; i<n; i++){
cin >> g >> h >> t;
edges[i] = {g, h, t};
v[g].push_back({h, t});
v[h].push_back({g, t});
}
for(int i=1; i<=n; i++){
dp1[i] = INF;
dp2[i] = INF;
}
for(int i=1; i<=s; i++){
cin >> g;
shop[g] = 1;
dp1[g] = 0;
dp2[g] = 0;
}
dfs(e, 0);
for(int i=1; i<20; i++){
for(int j=1; j<=n; j++){
par[j][i] = par[par[j][i - 1]][i - 1];
}
}
int u, v;
for(int i=1; i<=q; i++){
cin >> g >> h;
u = edges[g][0];
v = edges[g][1];
ans[i] = INF;
if(isanc(h, u) && isanc(h, v)){
if(d[u] < d[v]){
z[v].push_back({h, i});
}
else{
z[u].push_back({h, i});
}
ans[i] = dp1[h];
}
else{
ans[i] = -1;
}
}
dfs2(e, 0);
for(int i=1; i<=q; i++){
if(ans[i] == - 1){
cout << "escaped\n";
}
else if(ans[i] >= INF){
cout << "oo\n";
}
else{
cout << ans[i] << '\n';
}
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int T = 1;
//cin>>T;
while (T--){
solve();
}
}
