#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define pb push_back
#define ar array
#define all(x) x.begin(), x.end()
#define siz(x) (int)x.size()
#define FOR(x, y, z) for(int x = (y); x < (z); x++)
#define ROF(x, z, y) for(int x = (y-1); x >= (z); x--)
#define F0R(x, z) FOR(x, 0, z)
#define R0F(x, z) ROF(x, 0, z)
#define trav(x, y) for(auto&x:y)
using ll = long long;
using vi = vector<int>;
using vl = vector<long long>;
using pii = pair<int, int>;
using vpii = vector<pair<int, int>>;
template<class T> inline bool ckmin(T&a, T b) {return b < a ? a = b, 1 : 0;}
template<class T> inline bool ckmax(T&a, T b) {return b > a ? a = b, 1 : 0;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const char nl = '\n';
const int mxN = 1e5 + 10;
const int MOD = 1e9 + 7;
const long long infLL = 1e18;
int n, s, q, e;
vector<pair<int, ll>> adj[mxN];
bool shop[mxN];
int depth[mxN];
ll near[mxN];
ll dist[mxN];
int anc[mxN][20];
ll magic[mxN];
ll best[mxN][20];
pii edges[mxN];
void dfs(int u, int p){
anc[u][0] = p;
//cout << u << ' '<< dist[u] << nl;
FOR(i, 1, 20){
if(anc[u][i-1]==-1) anc[u][i] = -1;
else anc[u][i] = anc[anc[u][i-1]][i-1];
}
near[u] = infLL;
trav(v, adj[u]){
if(v.f == p) continue;
dist[v.f] = dist[u]+v.s;
depth[v.f] = depth[u]+1;
dfs(v.f, u);
ckmin(near[u], near[v.f]+v.s);
}
if(shop[u]) near[u] = 0;
magic[u] = -dist[u]+near[u];
best[u][0] = magic[u];
}
void dfs2(int u, int p){
//cout << u << ' ' << magic[u] << nl;
FOR(i, 1, 20){
if(anc[u][i-1]==-1) best[u][i]=magic[u];
else best[u][i] = min(best[anc[u][i-1]][i-1], best[u][i-1]);
}
trav(v, adj[u]){
if(v.f!=p){
dfs2(v.f, u);
}
}
}
int lca(int e1, int e2){
if(depth[e1] < depth[e2]){
swap(e1, e2);
}
int Dist = depth[e1] - depth[e2];
R0F(i, 20){
if((Dist)&(1<<i)){
e1 = anc[e1][i];
}
}
assert(depth[e1]==depth[e2]);
if(e1 == e2) return e1;
R0F(i, 20){
if(anc[e1][i]!=anc[e2][i]) e1 = anc[e1][i], e2 = anc[e2][i];
}
assert(anc[e1][0] == anc[e2][0]);
return anc[e1][0];
}
int32_t main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> s >> q >> e; e--;
F0R(i, n-1){
int e1, e2, e3;
cin >> e1 >> e2 >> e3; e1--; e2--;
edges[i] = {e1, e2};
adj[e1].pb({e2, e3});
adj[e2].pb({e1, e3});
}
F0R(i, s){
int e1; cin >> e1;
shop[e1-1] = 1;
}
dfs(e, -1);
dfs2(e, -1);
F0R(qq, q){
int i, r;
cin >> i >> r;
i--; r--;
if(depth[edges[i].f]<depth[edges[i].s]) swap(edges[i].f, edges[i].s);
int ans = lca(edges[i].f, r);
if(ans != edges[i].f) cout << "escaped\n";
else{
ll res = infLL;
int R = r;
F0R(j, 20){
if((depth[R]-depth[edges[i].f]+1)&(1<<j)){
ckmin(res, dist[R]+best[r][j]);
r=anc[r][j];
}
}
if(res>=(ll)1e15) cout << "oo\n";
else cout << res << nl;
}
}
return 0;
}
