#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define int long long
using namespace std;
const int mod = 1e9+7;
const ll inf = 1e18;
const int N = 2e5+5;
int n,s,q,e, a[N], U[N], V[N], W[N], up[N][20], timer = 0, tin[N], tout[N];
vector<int>g2[N];
set<pair<int,int>>g[N];
void dfs(int v, int p) {
tin[v] = ++timer;
up[v][0] = p;
for(int i = 1;i<20;i++) {
up[v][i] = up[up[v][i-1]][i-1];
}
for(auto to:g2[v]) {
if(to == p) continue;
dfs(to,v);
}
tout[v] = timer;
}
bool check(int a, int b) {
return tin[a]<=tin[b] && tout[a]>=tout[b];
}
void solve() {
cin >> n >> s >> q >> e;
vector<pair<int,int>>edjes;
for(int i = 1;i<n;i++) {
cin >> U[i] >> V[i] >> W[i];
g2[U[i]].pb(V[i]);
g2[V[i]].pb(U[i]);
g[U[i]].insert({V[i],W[i]});
g[V[i]].insert({U[i],W[i]});
}
for(int i = 1;i<=s;i++) {
cin >> a[i];
}
if(s == n) {
dfs(e,e);
while(q--) {
int i, r;
cin >> i >> r;
int u = U[i], v=V[i];
int c = (up[v][0] == u ? v : u);
if(check(c,r) == check(c,e)) {
cout << "escaped\n";
} else {
cout << "0\n";
}
}
} else {
while(q--){
int i,r;
cin >> i >> r;
int uu = U[i], vv =V[i], ww = W[i];
g[uu].erase({vv,ww});
g[vv].erase({uu,ww});
vector<int>dist(n+1,inf);
dist[r] = 0;
set<pair<int,int>>st;
st.insert({0,r});
while(st.size()) {
auto [dv,ver] = *st.begin();
st.erase(st.begin());
for(auto [to,weight]:g[ver]) {
if(dist[to]>dist[ver]+weight) {
st.erase({dist[to],to});
dist[to] = dist[ver]+weight;
st.insert({dist[to],to});
}
}
}
if(dist[e]!=inf) {
cout << "escaped\n";
}
else {
int mn = 1e18;
for(int i = 1;i<=s;i++) {
if(dist[a[i]]!=inf) {
mn = min(mn,dist[a[i]]);
}
}
if(mn == 1e18) {
cout << "oo\n";
} else {
cout << mn << "\n";
}
}
g[uu].insert({vv,ww});
g[vv].insert({uu,ww});
}
}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int tt=1;
//cin >> tt;
while(tt--) {
solve();
}
return 0;
}
