#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC target ("sse4")
#define endl "\n"
typedef long long ll;
template<class T, class T2> inline ostream &operator <<(ostream &out, const pair<T, T2> &x) { out << x.first << " " << x.second; return out;}
template<class T, class T2> inline istream &operator >>(istream &in, pair<T, T2> &x) { in >> x.first >> x.second; return in;}
template<class T, class T2> inline bool chkmax(T &x, const T2 &y) { return x < y ? x = y, 1 : 0; }
template<class T, class T2> inline bool chkmin(T &x, const T2 &y) { return x > y ? x = y, 1 : 0; }
const ll mod = 1e15 + 7;
#define debug(...) cout << "Line: " << __LINE__ << endl; \
printDebug(", "#__VA_ARGS__, __VA_ARGS__)
template <typename T>
void printDebug(const char* name, T&& arg1) { cout << (name + 2) << " = " << arg1 << endl; }
template <typename T, typename... T2>
void printDebug(const char* names, T&& arg1, T2&&... args) {
const char* end = strchr(names + 1, ',');
cout.write(names + 2, end - names - 2) << " = " << arg1 << endl;
printDebug(end, args...);
}
const ll MAX_N = 1e5 + 10, LOG = 20;
ll par[MAX_N][LOG], mn[MAX_N][LOG];
ll dp[MAX_N], help_dp[MAX_N];
ll d[MAX_N], in[MAX_N], out[MAX_N], tme = -1;
vector<pair<ll, ll> > g[MAX_N];
ll n, s, q, e;
bool good[MAX_N];
void dfs(ll x, ll p) {
dp[x] = help_dp[x] = mod;
in[x] = out[x] = ++ tme;
for(auto it : g[x]) {
if(it.first == p) {continue;}
d[it.first] = d[x] + it.second;
dfs(it.first, x);
chkmin(dp[x], help_dp[it.first] - 2 * d[x]);
chkmin(help_dp[x], help_dp[it.first]);
out[x] = out[it.first];
}
if(good[x]) {
dp[x] = -d[x];
help_dp[x] = d[x];
}
}
void lca_calc(ll x, ll p) {
par[x][0] = p;
mn[x][0] = min(dp[x], dp[p]);
for(ll i = 1; i < LOG; i ++) {
par[x][i] = par[par[x][i - 1]][i - 1];
mn[x][i] = min(mn[par[x][i - 1]][i - 1], mn[x][i - 1]);
}
for(auto it : g[x]) {
if(it.first == p) {continue;}
lca_calc(it.first, x);
}
}
ll ans(ll x, ll y) {
ll ret = dp[x];
for(ll i = LOG - 1; i >= 0; i --) {
if(d[par[x][i]] >= d[y]) {
chkmin(ret, mn[x][i]);
x = par[x][i];
}
}
return ret;
}
pair<ll, ll> edges[MAX_N];
signed main() {
// ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n >> s >> q >> e;
for(ll i = 0; i < n - 1; i ++) {
ll a, b, c;
cin >> a >> b >> c;
g[a].push_back({b, c});
g[b].push_back({a, c});
edges[i + 1] = {a, b};
}
for(ll i = 0; i < s; i ++) {
ll a;
cin >> a;
good[a] = true;
}
dfs(e, 0);
for(int i = 0; i < LOG; i ++) {
mn[1][i] = mod;
mn[0][i] = mod;
}
dp[0] = mod;
lca_calc(e, 0);
for(ll i = 0; i < q; i ++) {
ll a, ind;
cin >> ind >> a;
ll lower;
if(d[edges[ind].first] > d[edges[ind].second]) {
lower = edges[ind].first;
} else {
lower = edges[ind].second;
}
if(in[lower] <= in[a] && in[a] <= out[lower]) {
ll best_lca = ans(a, lower);
if(best_lca == mod) {
cout << "oo" << endl;
} else {
cout << best_lca + d[a] << endl;
}
} else {
cout << "escaped" << endl;
}
}
return 0;
}
/*
5 2 100 1
1 2 1
2 3 2
3 4 3
4 5 2
3 5
1 5
*/
