#include <bits/stdc++.h>
using namespace std;
#define int long long
const int mxN = 1e5 + 100;
const int INF = 1e9;
vector<pair<int, int>> adj[mxN];
int par[mxN], depth[mxN], head[mxN], heavy[mxN], sz[mxN], lt[mxN], val[mxN], dp[mxN], path_sum[mxN], seg[mxN * 4], tin[mxN], tout[mxN], st[mxN], t = -1, t2 = -1;
struct seg_tree1{
void build(int node, int start, int end){
if(start == end){
seg[node] = lt[start];
return;
}
int mid = start + (end - start) / 2;
build(node * 2 + 1, start, mid);
build(node * 2 + 2, mid + 1, end);
seg[node] = min(seg[node * 2 + 1], seg[node * 2 + 2]);
}
int query(int node, int start, int end, int l, int r){
if(start > r || end < l) return INF;
if(start >= l && end <= r) return seg[node];
int mid = start + (end - start) / 2;
return min(query(node * 2 + 1, start, mid, l, r), query(node * 2 + 2, mid + 1, end, l, r));
}
} tr;
struct hld{
void dfs(int u = 1, int p = 0){
depth[u] = depth[p] + 1;
par[u] = p;
sz[u] = 1;
tin[u] = ++t2;
for(auto it : adj[u]){
if(it.first ^ p){
path_sum[it.first] = path_sum[u] + it.second;
dfs(it.first, u);
dp[u] = min(dp[u], dp[it.first] + it.second);
if(sz[heavy[u]] < sz[it.first]){
heavy[u] = it.first;
}
}
}
tout[u] = ++t2;
}
void dfs_hld(int u = 1, int chain = 1, int p = 0){
head[u] = chain;
lt[++t] = dp[u] - path_sum[u];
st[u] = t;
if(heavy[u] > 0){
dfs_hld(heavy[u], chain, u);
}
for(auto it : adj[u]){
if(it.first ^ p && heavy[it.first] ^ it.first){
dfs_hld(it.first, it.first, u);
}
}
}
bool subtree(int u, int v){
return tin[v] >= tin[u] && tout[v] <= tout[u];
}
int query(int u, int v) {
int ans = INF;
while(head[u] != head[v]) {
ans = min(ans, tr.query(0, 0, t, st[head[u]], st[u]));
u = par[head[u]];
}
ans = min(ans, tr.query(0, 0, t, st[v], st[u]));
return ans;
}
} hld;
signed main(){
#ifndef ONLINE_JUDGE
freopen("input.in", "r", stdin);
freopen("output.out", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
int n, s, q, e, u, v, w, edge_id;
cin >> n >> s >> q >> e;
vector<pair<int, int>> edge;
for(int i = 0; i < n - 1; ++i){
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
edge.push_back({u, v});
}
for(int i = 1; i <= n; ++i){
dp[i] = INF;
}
for(int i = 0; i < s; ++i){
cin >> u;
dp[u] = 0;
}
hld.dfs(e, 0);
hld.dfs_hld(e, e, 0);
tr.build(0, 0, t);
while(q--){
cin >> edge_id >> u; --edge_id;
int u1 = edge[edge_id].first, u2 = edge[edge_id].second;
if(hld.subtree(u1, u) && hld.subtree(u2, u) && u != e){
if(depth[u1] < depth[u2]) swap(u1, u2);
int curr = hld.query(u, u1) + path_sum[u];
if(curr >= INF){
cout << "oo\n";
}else{
cout << curr << "\n";
}
}else{
cout << "escaped\n";
}
}
return 0;
}
