#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 1e18+9;
template<class Info, class Tag>
struct LazySegmentTree {
int n;
vector<Info> info;
vector<Tag> tag;
LazySegmentTree() : n(0) {}
LazySegmentTree(int n_, Info v_ = Info()) {
init(n_, v_);
}
template<class T>
LazySegmentTree(vector<T> init_) {
init(init_);
}
void init(int n_, Info v_ = Info()) {
init(vector<Info>(n_, v_));
}
template<class T>
void init(vector<T> init_) {
n = init_.size();
info.assign(4 << __lg(n), Info());
tag.assign(4 << __lg(n), Tag());
function<void(int, int, int)> build = [&](int p, int l, int r) {
if (r - l == 1) {
info[p] = init_[l];
return;
}
int m = (l + r) / 2;
build(2 * p, l, m);
build(2 * p + 1, m, r);
pull(p);
};
build(1, 0, n);
}
void pull(int p) {
info[p] = info[2 * p] + info[2 * p + 1];
}
void apply(int p, const Tag &v) {
info[p].apply(v);
tag[p].apply(v);
}
void push(int p) {
apply(2 * p, tag[p]);
apply(2 * p + 1, tag[p]);
tag[p] = Tag();
}
void modify(int p, int l, int r, int x, const Info &v) {
if (r - l == 1) {
info[p] = v;
return;
}
int m = (l + r) / 2;
push(p);
if (x < m) {
modify(2 * p, l, m, x, v);
} else {
modify(2 * p + 1, m, r, x, v);
}
pull(p);
}
void modify(int p, const Info &v) {
modify(1, 0, n, p, v);
}
Info rangeQuery(int p, int l, int r, int x, int y) {
if (l >= y || r <= x) {
return Info();
}
if (l >= x && r <= y) {
return info[p];
}
int m = (l + r) / 2;
push(p);
return rangeQuery(2 * p, l, m, x, y) + rangeQuery(2 * p + 1, m, r, x, y);
}
Info rangeQuery(int l, int r) {
return rangeQuery(1, 0, n, l, r);
}
void rangeApply(int p, int l, int r, int x, int y, const Tag &v) {
if (l >= y || r <= x) {
return;
}
if (l >= x && r <= y) {
apply(p, v);
return;
}
int m = (l + r) / 2;
push(p);
rangeApply(2 * p, l, m, x, y, v);
rangeApply(2 * p + 1, m, r, x, y, v);
pull(p);
}
void rangeApply(int l, int r, const Tag &v) {
return rangeApply(1, 0, n, l, r, v);
}
template<class F>
int findFirst(int p, int l, int r, int x, int y, F &&pred) {
if (l >= y || r <= x) {
return -1;
}
if (l >= x && r <= y && !pred(info[p])) {
return -1;
}
if (r - l == 1) {
return l;
}
int m = (l + r) / 2;
push(p);
int res = findFirst(2 * p, l, m, x, y, pred);
if (res == -1) {
res = findFirst(2 * p + 1, m, r, x, y, pred);
}
return res;
}
template<class F>
int findFirst(int l, int r, F &&pred) {
return findFirst(1, 0, n, l, r, pred);
}
template<class F>
int findLast(int p, int l, int r, int x, int y, F &&pred) {
if (l >= y || r <= x) {
return -1;
}
if (l >= x && r <= y && !pred(info[p])) {
return -1;
}
if (r - l == 1) {
return l;
}
int m = (l + r) / 2;
push(p);
int res = findLast(2 * p + 1, m, r, x, y, pred);
if (res == -1) {
res = findLast(2 * p, l, m, x, y, pred);
}
return res;
}
template<class F>
int findLast(int l, int r, F &&pred) {
return findLast(1, 0, n, l, r, pred);
}
};
struct Tag {
ll add = 0;
void apply(const Tag &t) & {
add += t.add;
}
};
struct Info {
ll mn = INF;
void apply(const Tag &t) & {
mn += t.add;
}
Info operator+(const Info &b) {
return {min(mn, b.mn)};
}
};
struct edge{
ll u, v, w;
};
struct que{
int I, R, id;
};
void solve(){
int n, S, Q, H;
cin >> n >> S >> Q >> H;
vector<vector<pair<ll, ll>>> adj(n+1);
vector<edge> e(n);
for(int i = 1; i < n; i++){
ll u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
e[i] = {u, v, w};
}
vector<bool> is_special(n+1, false);
for(int i = 1; i <= S; i++){
int x;
cin >> x;
is_special[x] = true;
}
vector<que> q(Q+1);
for(int i = 1; i <= Q; i++){
cin >> q[i].I >> q[i].R;
q[i].id = i;
}
int timer = 0;
vector<int> rt(n+1), lt(n+1);
vector<ll> f(n+1, INF);
vector<int> depth(n+1, -1);
auto root_tree = [&](auto root_tree, int u, int p, ll len) -> void{
timer ++;
lt[u] = timer;
depth[u] = depth[p]+1;
if(is_special[u]){
f[u] = len;
}else{
f[u] = INF;
}
for(auto it : adj[u]){
int v = it.first;
ll w = it.second;
if(v == p) continue;
root_tree(root_tree, v, u, len+w);
}
rt[u] = timer;
};
root_tree(root_tree, H, 0, 0);
for(int i = 1; i < n; i++){
if(depth[e[i].u] > depth[e[i].v]){
swap(e[i].u, e[i].v);
}
}
vector<vector<que>> b(n+1);
for(int i = 1; i <= Q; i++){
b[q[i].R].push_back(q[i]);
}
LazySegmentTree<Info, Tag> T(n+1);
for(int i = 1; i <= n; i++){
T.modify(lt[i], {f[i]});
}
vector<ll> ans(Q+1, -3);
auto is_anc = [&](int u, int v) -> bool{
return lt[u] <= lt[v] && lt[v] <= rt[u];
};
for(int i = 1; i <= Q; i++){
int v = e[q[i].I].v;
if(!is_anc(v, q[i].R)){
ans[i] = -2;
}
}
auto dfs = [&](auto dfs, int u, int p) -> void{
for(auto it : b[u]){
ll res = INF;
int id = it.id;
if(ans[id] == -2) continue;
int v = e[it.I].v;
if(is_anc(v, u)){
res = T.rangeQuery(lt[v], rt[v]+1).mn;
}else{
res = min(T.rangeQuery(1, lt[v]).mn, T.rangeQuery(rt[v]+1, n+1).mn);
}
if(res >= 1e15){
ans[id] = -1;
}else{
ans[id] = res;
}
}
for(auto it : adj[u]){
int v = it.first;
ll w = it.second;
if(v == p) continue;
ll prv_fu, prv_fv, fu, fv;
T.rangeApply(1, lt[v], {w});
T.rangeApply(rt[v]+1, n+1, {w});
T.rangeApply(lt[v], rt[v]+1, {-w});
dfs(dfs, v, u);
T.rangeApply(1, lt[v], {-w});
T.rangeApply(rt[v]+1, n+1, {-w});
T.rangeApply(lt[v], rt[v]+1, {w});
}
};
dfs(dfs, H, 0);
for(int i = 1; i <= Q; i++){
if(ans[i] == -2){
cout << "escaped";
}
if(ans[i] == -1){
cout << "oo";
}
if(ans[i] >= 0){
cout << ans[i];
}
cout << "\n";
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
solve();
}
