#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<class T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define ll long long int
#define lli long long int
#define pii pair<ll,ll>
#define all(x) x.begin(),x.end()
#define mk make_pair
#define pb push_back
#define se second
#define fi first
#define nn '\n'
#define lc (id << 1)
#define rc ((id << 1) ^ 1)
#define mid (l + r) / 2
#define txt freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);
#define T int T;cin>>T;while(T--)
#define ashar(x) fixed<<setprecision(x)
#define migmig ios_base::sync_with_stdio(0);cin.tie(0);
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const lli maxn = 2e5 + 10, mod = 998244353, sq = 400, lg = 22, inf = 1e18;
ll pw(ll a, ll b) { return (!b ? 1 : (b & 1 ? a * pw(a * a % mod, b / 2) % mod : pw(a * a % mod, b / 2) % mod)); }
ll n, m, s, q, r, k = 1;
ll up[lg][maxn], mn[lg][maxn], d[maxn], h[maxn], st[maxn], fn[maxn];
bool sh[maxn];
vector<pii> e[maxn], adj;
void dfs(ll v, ll par = r){
st[v] = k++;
d[v] = (sh[v] ? 0 : inf);
up[0][v] = par;
for(int i = 1; i < lg; i++){
up[i][v] = up[i - 1][up[i - 1][v]];
}
for(auto [u, w] : e[v]){
if(u != par){
h[u] = h[v] + w;
dfs(u, v);
d[v] = min(d[v], d[u] + w);
}
}
fn[v] = k;
}
void dfs2(ll v, ll par = r){
mn[0][v] = d[v] - h[v];
for(int i = 1; i < lg; i++){
mn[i][v] = min(mn[i - 1][v], mn[i - 1][up[i - 1][v]]);
}
for(auto [u, w] : e[v]){
if(u != par) dfs2(u, v);
}
}
int main(){
migmig;
cin >> n >> s >> q >> r;
ll u, v, w;
for(int i = 1; i < n; i++){
cin >> u >> v >> w;
adj.pb({u, v});
e[u].pb({v, w});
e[v].pb({u, w});
}
for(int i = 1; i <= s; i++){
cin >> v;
sh[v] = 1;
}
dfs(r);
dfs2(r);
ll x;
while(q--){
cin >> x >> v;
x--;
if(st[v] < max(st[adj[x].fi], st[adj[x].se]) || st[v] >= min(fn[adj[x].fi], fn[adj[x].se])){
cout << "escaped" << nn;
}
else{
ll ans = d[v], u = v;
for(int i = lg - 1; i >= 0; i--){
if(h[up[i][u]] >= min(h[adj[x].fi], h[adj[x].se])){
ans = min(mn[i][u] + h[v], ans);
//cerr << mn[i][u] << " " << u << " " << i << " " << up[i][u] << nn;
u = up[i][u];
}
}
if(ans == inf) cout << "oo" << nn;
else cout << ans << nn;
}
}
}
// Deathly mistakes:
// * Read the problem carefully.
// * Check maxn.
// * Overflows.
