#include<bits/stdc++.h>
#define int long long
#define sz(x) (int) x.size()
#define all(x) x.begin(), x.end()
using namespace std;
struct Edge{
int u, v, w;
};
const int INF = 1e15;
const int N = 1e5+5;
Edge edges[N];
vector<pair<int,int>> E[N];
int par[20][N], val[20][N];
int dist[N], dep[N];
int st[N], ed[N];
bool shop[N];
int n, s, q, root, t = 0;
int dfs(int u, int p) {
dist[u] += dist[p];
dep[u] = dep[p] + 1;
par[0][u] = p;
st[u] = ++t;
int res = INF;
for(auto [v, w]: E[u]) {
if(v == p) continue;
dist[v] = w;
res = min(res, dfs(v, u));
}
ed[u] = t;
if(shop[u]) res = min(res, dist[u]);
if(res!= INF) val[0][u] = res - 2*dist[u];
else val[0][u] = INF;
return res;
}
void build() {
for(int k=1; k<20; k++) {
for(int i=1; i<=n; i++) {
par[k][i] = par[k-1][par[k-1][i]];
val[k][i] = min(val[k-1][i], val[k-1][par[i-1][i]]);
}
}
}
int find_val_min(int u, int p) {
int d = dep[u] - dep[p];
int res = INF;
for(int k=0; k<20; k++) {
if(d&(1<<k)) {
res = min(res, val[k][u]);
u = par[k][u];
}
}
return min(res, val[0][u]);
}
bool is_ancestor(int u, int p) {
return (st[p] <= st[u] && ed[u] <=ed[p]);
}
void solve() {
cin >> n >> s >> q >> root;
for(int i=1; i<n; i++) {
int u, v, w; cin >> u >> v >> w;
E[u].push_back({v, w});
E[v].push_back({u, w});
edges[i] = {u, v, w};
}
for(int i=1; i<=s; i++) {
int u; cin >> u ;
shop[u] = true;
}
dfs(root, 0);
build();
while(q--) {
int id, x; cin >> id >> x;
auto[u, v, w] = edges[id];
if(dep[u] < dep[v]) swap(u, v);
if(!is_ancestor(x, u)) cout<<"escaped\n";
else {
int res = find_val_min(x, u);
if(res == INF) cout<<"oo\n";
else {
cout<< dist[x] + res <<'\n';
}
}
}
}
signed main() {
if(fopen("input.txt", "r")) freopen("input.txt", "r", stdin);
ios_base::sync_with_stdio(false);cin.tie(0);
int T = 1;
// cin >> T;
while(T--) solve();
}
