#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair<int,int>
#define f first
#define s second
#define chmin(a, b) a = min(a,b)
#define chmax(a, b) a = max(a,b)
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define all(x) x.begin(),x.end()
#define v vector
const int MAX_N = 100000, l2d = 17;
v<pii> adj[MAX_N];
v<pii> queries[MAX_N];
pair<pii,int> edges[MAX_N];
ll ans[MAX_N];
int on_stack[MAX_N];
ll lift[MAX_N][l2d], store[MAX_N][l2d];
void dfs(int cur, int par, int d, ll len) {
if (store[cur][0]==0) {store[cur][0] -= len;}
on_stack[cur] = d;
v<pii> nxt;
for (pii x : queries[cur]) {
int a = on_stack[edges[x.f].f.f], b = on_stack[edges[x.f].f.s];
if (a && b) {
int mn = (a<b ? edges[x.f].f.s : edges[x.f].f.f);
nxt.pb({d-min(a,b),x.s});
} else {ans[x.s] = -2;} // escape
}
queries[cur] = nxt;
for (pii x : adj[cur]) {
if (x.f!=par) {
lift[x.f][0] = cur;
dfs(x.f,cur,d+1,len+x.s);
if (store[x.f][0]!=LLONG_MAX) {
chmin(store[cur][0],store[x.f][0]+2*x.s);
}
}
}
on_stack[cur] = 0;
}
void dfs2(int cur, int par, ll len) {
for (pii x : queries[cur]) {
ll dist = LLONG_MAX, c = cur;
F0R(b,l2d) {
if (x.f&(1<<b)) {
chmin(dist,store[c][b]);
c = lift[c][b];
}
} if (dist!=LLONG_MAX) {ans[x.s] = dist+len;}
}
for (pii x : adj[cur]) {
if (x.f!=par) {
dfs2(x.f,cur,len+x.s);
}
}
}
int main() {
ios::sync_with_stdio(false); cin.tie(0);
int n, s, q, e; cin >> n >> s >> q >> e;
F0R(i,n-1) {
int a, b, w; cin >> a >> b >> w;
adj[--a].pb({--b,w}); adj[b].pb({a,w});
edges[i] = {{a,b},w};
}
memset(ans,-1,sizeof(ans));
memset(lift,-1,sizeof(lift));
F0R(i,n) {F0R(j,l2d) {store[i][j] = LLONG_MAX;}}
F0R(i,s) {
int a; cin >> a;
store[--a][0] = 0;
}
F0R(i,q) {
int a, b; cin >> a >> b;
queries[--b].pb({--a,i});
}
dfs(--e,-1,1,0);
FOR(p,1,l2d) {
F0R(i,n) {
if (lift[i][p-1]!=-1) {
lift[i][p] = lift[lift[i][p-1]][p-1];
store[i][p] = min(store[i][p-1],store[lift[i][p-1]][p-1]);
}
}
}
dfs2(e,-1,0);
F0R(i,q) {
if (ans[i]==-1) {cout << "oo";}
else if (ans[i]==-2) {cout << "escaped";}
else {cout << ans[i];}
cout << '\n';
}
/*
root tree at E
if edge endpoints are ancestors of P then it can't reach E
otherwise, find nearest shop
find nearest shop in subtree of i for each i
limited to some rmq thing for dfs traversal
binary lifting rmq maybe
let nearest shop be at distance i, then the effective weight of this node
is pathlength+i, and take the minimum weight
subtract pathlength from all weights, so it's just i-pathlengthtoroot
at end, add back pathlengthtoroot to get total length
*/
}
