///*** Sown_Vipro ***///
/// ->TUYEN QUOC GIA<- ///
#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define pb push_back
#define inp(name) if(fopen(name, "r")) freopen(name, "r", stdin);
#define out(name) if(fopen(name, "w")) freopen(name, "w", stdout);
const int N = 1e5 + 5, MAX = 1e9 + 5, MOD = 1e9 + 7;
int n, s, q, spe, TIME;
vector<pair<int, int> > adj[N];
int in[N], out[N], check[N], vt[N], cnt[N], l1[N], r1[N], l2[N], r2[N];
queue<int> pq[N];
long long g[N], ans[N];
void dfs(int u, int p){
in[u] = ++TIME;
vt[TIME] = u;
if(check[u]) ++cnt[u];
for(pair<int, int> edge : adj[u]){
int v = edge.F, w = edge.S;
if(v == p) continue;
g[v] = g[u] + w;
dfs(v, u);
cnt[u] += cnt[v];
}
out[u] = TIME;
}
struct edge{
int u, v;
} e[N];
int isChild(int u, int v){
if(in[u] <= in[v] && out[u] >= out[v]) return 1;
return 0;
}
long long st[4 * N], lz[4 * N];
void build(int id, int l, int r){
if(l == r){
if(check[vt[l]]) st[id] = g[vt[l]];
else st[id] = 1e18;
return;
}
int m = (l + r) / 2;
build(2 * id, l, m);
build(2 * id + 1, m + 1, r);
st[id] = min(st[2 * id], st[2 * id + 1]);
}
void down(int id){
st[2 * id] += lz[id];
st[2 * id + 1] += lz[id];
lz[2 * id] += lz[id];
lz[2 * id + 1] += lz[id];
lz[id] = 0;
}
void update(int id, int l, int r, int u, int v, int w){
if(l > v || r < u) return;
if(u <= l && r <= v){
st[id] += w;
lz[id] += w;
return;
}
down(id);
int m = (l + r) / 2;
update(2 * id, l, m, u, v, w);
update(2 * id + 1, m + 1, r, u, v, w);
st[id] = min(st[2 * id], st[2 * id + 1]);
}
long long get(int id, int l, int r, int u, int v){
if(l > v || r < u) return 1e18;
if(u <= l && r <= v){
return st[id];
}
down(id);
int m = (l + r) / 2;
return min(get(2 * id, l, m, u, v), get(2 * id + 1, m + 1, r, u, v));
}
void result(int u, int p, int c){
update(1, 1, n, in[u], out[u], -c);
update(1, 1, n, 1, in[u] - 1, c);
update(1, 1, n, out[u] + 1, n, c);
while(pq[u].size()){
int id = pq[u].front();
pq[u].pop();
if(!l2[id]){
ans[id] = get(1, 1, n, l1[id], r1[id]);
}else{
ans[id] = min(get(1, 1, n, l1[id], r1[id]), get(1, 1, n, l2[id], r2[id]));
}
}
for(pair<int, int> edge : adj[u]){
int v = edge.F, w = edge.S;
if(v == p) continue;
result(v, u, w);
}
update(1, 1, n, in[u], out[u], c);
update(1, 1, n, 1, in[u] - 1, -c);
update(1, 1, n, out[u] + 1, n, -c);
}
void solve(){
cin >> n >> s >> q >> spe;
for(int i = 1; i < n; ++i){
int u, v, w; cin >> u >> v >> w;
adj[u].pb({v, w});
adj[v].pb({u, w});
e[i] = {u, v};
}
for(int i = 1; i <= s; ++i){
int u; cin >> u;
check[u] = 1;
}
dfs(1, 0);
build(1, 1, n);
for(int i = 1; i <= q; ++i){
int id, r; cin >> id >> r;
int u = e[id].u, v = e[id].v;
if(in[u] > in[v]) swap(u, v);
if(isChild(v, r) == isChild(v, spe)){
ans[i] = 1;
}else{
if(isChild(v, r)){
if(cnt[v] == 0){
ans[i] = -1;
}else{
l1[i] = in[v];
r1[i] = out[v];
pq[r].push(i);
}
}else{
if(cnt[1] - cnt[v] == 0) ans[i] = -1;
else{
l1[i] = 1;
r1[i] = in[v] - 1;
l2[i] = out[v] + 1;
r2[i] = n;
pq[r].push(i);
}
}
}
}
result(1, 0, 0);
for(int i = 1; i <= q; ++i){
if(ans[i] == 1) cout << "escaped\n";
else if(ans[i] == -1) cout << "oo\n";
else cout << ans[i] << "\n";
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
inp("in.txt");
solve();
}
