#pragma GCC optimize("O2")
#include <bits/stdc++.h>
#ifdef DEBUG
#include "debug.hpp"
#endif
using namespace std;
#define all(c) (c).begin(), (c).end()
#define traverse(c, it) for(auto it = (c).begin(); it != (c).end(); it++)
#define rep(i, N) for(int i = 0; i < (N); i++)
#define rep1(i, N) for(int i = 1; i <= (N); i++)
#define rep2(i, s, e) for(int i = (s); i <= (e); i++)
#define rep3(i, s, e, d) for(int i = (s); (d) >= 0 ? i <= (e) : i >= (e); i += (d))
#define pb push_back
#ifdef DEBUG
#define debug(x...) {dbg::depth++; string dbg_vals = dbg::to_string(x); dbg::depth--; dbg::fprint(__func__, __LINE__, #x, dbg_vals);}
#define light_debug(x) {dbg::light = 1; dbg::dout << __func__ << ":" << __LINE__ << " " << #x << " = " << x << endl; dbg::light = 0;}
#else
#define debug(x...)
#define light_debug(x)
#endif
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
struct edge{
int u, v, w;
};
int N, S, Q, E;
vector<vector<edge>> adj;
vector<edge> edges;
vector<vi> par, RMQ_set;
vi is_shop, dp_set, in_time, out_time;
vector<ll> dp, dist;
vector<vector<ll>> RMQ;
void init(){
adj.resize(N);
dist.resize(N);
dp.resize(N);
is_shop.resize(N);
dp_set.resize(N);
in_time.resize(N);
out_time.resize(N);
edges.resize(N - 1);
par = vector<vi>(N, vi(__lg(N) + 1, E));
RMQ = vector<vector<ll>>(N, vector<ll>(__lg(N) + 1));
RMQ_set = vector<vi>(N, vi(__lg(N) + 1));
}
int cur_time = 0;
void dfs(int v, int p, ll d){
in_time[v] = cur_time++;
debug(v);
par[v][0] = p, dist[v] = d;
if(is_shop[v])
dp[v] = -d, dp_set[v] = 1;
for(auto e : adj[v]){
int u = v ^ e.v ^ e.u;
if(u != p){
dfs(u, v, d + e.w);
if(dp_set[u]){
if(!dp_set[v])
dp[v] = dp[u] + 2 * e.w, dp_set[v] = 1;
else
dp[v] = min(dp[v], dp[u] + 2 * e.w);
}
}
}
out_time[v] = cur_time;
}
inline bool is_ancestor(int u, int v){
return in_time[u] <= in_time[v] && out_time[v] <= out_time[u];
}
inline void xmin(ll a, int set_a, ll b, int set_b, ll& c, int& set_c){
set_c = set_a || set_b;
if(set_a && set_b)
c = min(a, b);
else if(set_a)
c = a;
else if(set_b)
c = b;
}
void init_RMQ(){
rep1(k, __lg(N))
rep(i, N)
par[i][k] = par[par[i][k - 1]][k - 1];
rep(i, N)
RMQ_set[i][0] = dp_set[i], RMQ[i][0] = dp[i];
rep1(k, __lg(N))
rep(i, N)
xmin(RMQ[i][k - 1], RMQ_set[i][k - 1], RMQ[par[i][k - 1]][k - 1], RMQ_set[par[i][k - 1]][k - 1], RMQ[i][k], RMQ_set[i][k]);
}
pair<int, ll> nearest_shop(int r, int t){
assert(is_ancestor(t, r));
debug(r, t);
ll d = dist[r];
ll ans = -1;
int set_ans = 0;
int k = __lg(N);
while(r != t){
int x = par[r][k];
debug(x, k);
if(!is_ancestor(x, par[t][0]))
xmin(RMQ[r][k], RMQ_set[r][k], ans, set_ans, ans, set_ans), r = x;
k--;
}
xmin(ans, set_ans, RMQ[t][0], RMQ_set[t][0], ans, set_ans);
return {set_ans, ans + d};
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
#ifdef DEBUG
freopen("debug", "w", stderr);
#endif
cin >> N >> S >> Q >> E;
E--;
init();
rep(i, N - 1){
cin >> edges[i].u >> edges[i].v >> edges[i].w;
edges[i].u--, edges[i].v--;
adj[edges[i].u].pb(edges[i]), adj[edges[i].v].pb(edges[i]);
}
rep(i, S){
int v;
cin >> v;
is_shop[--v] = 1;
}
dfs(E, E, 0);
init_RMQ();
rep(i, Q){
int e, r;
cin >> e >> r;
--e, --r;
int t = dist[edges[e].u] < dist[edges[e].v] ? edges[e].v : edges[e].u;
if(!is_ancestor(t, r))
cout << "escaped\n";
else{
auto p = nearest_shop(r, t);
cout << (p.first ? to_string(p.second) : "oo") << '\n';
}
}
#ifdef DEBUG
dbg::dout << "\nExecution time: " << clock() << "ms\n";
#endif
return 0;
}
