// #pragma GCC optimize("O3,Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define MP make_pair
#define pb push_back
#define REP(i,n) for(int i = 0; (i) < (n); (i)++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void fastio() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
}
const double EPS = 0.00001;
const int INF = 1e17;
const int N = 2e5+5;
const int ALPH = 26;
const int LGN = 20;
constexpr int MOD = 1e9+7;
const int MX = 1e16;
int n,m,q,s,e;
vector<vector<array<int,3> > > adj(N, vector<array<int,3> >());
vector<vector<int> > anc(LGN, vector<int>(N, 0)), mns(LGN, vector<int>(N, INF));
vector<int> tin(N, 0), dp(N, INF);
vector<bool> spec(N, 0);
vector<int> find_edge(N, 0), dep(N, 0);
vector<int> subt(N, 0), cost(N, 0);
int timer = 1;
void dfs(int node, int par) {
tin[node] = timer++;
anc[0][node] = par;
if(spec[node]) dp[node] = 0;
subt[node] = 1;
for(auto itr = adj[node].begin(); itr != adj[node].end();) {
auto &c = *itr;
if(c[0] == par) {
itr = adj[node].erase(itr);
continue;
}
find_edge[c[2]] = c[0];
dep[c[0]] = dep[node] + 1ll;
cost[c[0]] = cost[node] + c[1];
dfs(c[0], node);
subt[node] += subt[c[0]];
dp[node] = min(dp[node], dp[c[0]] + c[1]);
itr++;
}
}
void prec() {
for(int i = 1; i<=n; i++) mns[0][i] = dp[i];
for(int k = 1; k < LGN; k++) {
for(int i = 1; i <= n; i++) {
anc[k][i] = anc[k - 1][anc[k - 1][i]];
mns[k][i] = min(mns[k - 1][i], mns[k - 1][anc[k - 1][i]]);
}
}
}
int mindp(int x, int y) {
int ret = INF;
for(int k = LGN - 1; k >= 0; k--) {
if(dep[anc[k][x]] >= dep[y]) {
ret = min(ret, mns[k][x]);
x = anc[k][x];
}
}
ret = min(ret, mns[0][x]);
return ret;
}
inline void solve() {
cin>>n>>s>>q>>e;
REP(i, n - 1) {
int u, v, w;
cin >> u >> v >> w;
adj[u].pb({v, w, i + 1});
adj[v].pb({u, w, i + 1});
}
REP(i, s) {
int tmp;
cin >> tmp;
spec[tmp] = 1;
}
dfs(e, 0);
for(int i = 1; i<=n; i++) {
dp[i] -= cost[i];
}
prec();
REP(z, q) {
int I,R;
cin >> I >> R;
int sub = find_edge[I];
if(tin[sub] <= tin[R] && tin[R] <= tin[sub] + subt[sub] - 1ll) {
int ans = mindp(R, sub);
if(ans >= MX) {
cout << "oo\n";
}
else {
cout << ans + cost[R] << "\n";
}
}
else {
cout << "escaped\n";
}
}
}
signed main() {
fastio();
int test = 1;
//cin>>test;
while(test--) {
solve();
}
}
