#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int long long
#define FOR(i, a, b) for ( int i = a ; i <= b ; i++ )
#define FORD(i, a, b) for (int i = b; i >= a; i --)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPD(i, n) for (int i = n - 1; i >= 0; --i)
#define pii pair<int , int>
#define Lg(x) 31 - __builtin_clz(x)
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int MAX = 2e5 + 5;
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
void setupIO(){
#define name "Whisper"
//Phu Trong from Nguyen Tat Thanh High School for gifted student
srand(time(NULL));
cin.tie(nullptr)->sync_with_stdio(false); cout.tie(nullptr);
//freopen(name".inp", "r", stdin);
//freopen(name".out", "w", stdout);
cout << fixed << setprecision(10);
}
template <class X, class Y>
bool minimize(X &x, const Y &y){
X eps = 1e-9;
if (x > y + eps) {x = y; return 1;}
return 0;
}
template <class X, class Y>
bool maximize(X &x, const Y &y){
X eps = 1e-9;
if (x + eps < y) {x = y; return 1;}
return 0;
}
int numNode, numShop, numQuery, Exit;
int tin[MAX], tout[MAX], dep[MAX], d[MAX], hasShop[MAX];
int dis[MAX][23], up[MAX][23];
int cnt = 0;
int dp[MAX];
vector<pair<int, int>> adj[MAX];
void dfs(int u, int p = -1){
tin[u] = ++cnt;
dp[u] = (hasShop[u] ? 0 : LINF);
for (pair<int, int> &x : adj[u]){
int v = x.first, w = x.second;
if(v ^ p){
d[v] = d[u] + w;
dep[v] = dep[u] + 1;
up[v][0] = u;
dfs(v, u);
minimize(dp[u], dp[v] + w);
}
}
tout[u] = cnt;
for (int i = 1; i <= 21; ++i) dis[u][i] = LINF;
}
bool is_ancestor(int u, int v){
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
void pre_dfs(int u, int p = -1){
for (pair<int, int>&x : adj[u]){
int v = x.first, w = x.second;
if (v ^ p){
dis[v][0] = dp[u] - d[u];
for (int i = 1; i <= 21; ++i){
up[v][i] = up[up[v][i - 1]][i - 1];
dis[v][i] = min(dis[v][i - 1], dis[up[v][i - 1]][i - 1]);
}
pre_dfs(v, u);
}
}
}
int query(int u, int v){
int dist = dep[u] - dep[v];
int res = dp[u] - d[u];
for (int i = 0; MASK(i) <= dist; ++i){
if (BIT(dist, i)){
minimize(res, dis[u][i]); u = up[u][i];
}
}
return res;
}
void Whisper(){
cin >> numNode >> numShop >> numQuery >> Exit;
vector<array<int, 3>> edge(numNode + 1);
for (int i = 1; i < numNode; ++i){
int u, v, w; cin >> u >> v >> w;
edge[i] = {u, v, w};
adj[u].emplace_back(v, w);
adj[v].emplace_back(u, w);
}
for (int i = 1; i <= numShop; ++i){
int x; cin >> x;
hasShop[x] = 1;
}
dfs(Exit); pre_dfs(Exit);
for (int t = 1; t <= numQuery; ++t){
int i, r; cin >> i >> r;
int u = edge[i][0], v = edge[i][1];
if(dep[u] < dep[v]) swap(u, v);
if (!is_ancestor(u, r)) cout << "escaped\n";
else{
int ans = query(r, u) + d[r];
if (ans >= LINF) cout << "oo\n";
else cout << ans << '\n';
}
}
}
signed main(){
setupIO();
int Test = 1;
// cin >> Test;
for ( int i = 1 ; i <= Test ; i++ ){
Whisper();
if (i < Test) cout << '\n';
}
}
