#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<class T> using oset =
tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define int long long
#define ld long double
#define ar array
#define vi vector<int>
#define vii vector<vector<int>>
#define pii pair<int, int>
#define pb push_back
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define endl "\n"
const int MOD = 1e9+7;
const int inf = 1e9;
const int linf = 1e18;
const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// -------------------------------------------------- Main Code --------------------------------------------------
const int N = 1e5+5;
vector<pii> g[N];
int n, s, q, e, shop[N], parent[N][20], tin[N], tout[N], Time = 0, sub[N], depth[N], minimum[N][20], singleDepth[N];
void dfs(int src, int par) {
parent[src][0] = par;
tin[src] = ++Time;
if (shop[src]) minimum[src][0] = depth[src];
for (auto child : g[src]) {
int ch = child.f, wt = child.s;
if (ch == par) continue;
depth[ch] = depth[src] + wt;
singleDepth[ch] = singleDepth[src]+1;
dfs(ch, src);
minimum[src][0] = min(minimum[src][0], minimum[ch][0]);
}
tout[src] = Time;
}
int kthMin(int a, int k) {
int ans = linf;
for (int i = 0; i < 20; i++) {
if (k && (1<<i)) {
ans = min(ans, minimum[a][i]);
a = parent[a][i];
}
}
return ans;
}
void sol() {
for (int i = 0; i < N; i++) minimum[i][0] = linf;
cin >> n >> s >> q >> e;
vii edges;
for (int i = 1; i <= n-1; i++) {
int a, b, c; cin >> a >> b >> c;
g[a].pb({b, c}); g[b].pb({a, c});
edges.pb({a, b, c});
}
for (int i = 1; i <= s; i++) {int x; cin >> x; shop[x] = true;}
dfs(e, 0);
for (int i = 1; i <= n; i++) minimum[i][0] += (-2*(depth[i]));
for (int j = 1; j <= n-1; j++) {
auto i = edges[j-1];
if (i[0] != parent[i[1]][0]) swap(i[0], i[1]);
sub[j] = i[1];
}
for (int j = 1; j < 20; j++) {
for (int i = 1; i <= n; i++) {
parent[i][j] = parent[parent[i][j-1]][j-1];
minimum[i][j] = min(minimum[parent[i][j-1]][j-1], minimum[i][j-1]);
}
}
while (q--) {
int root, r; cin >> root >> r;
root = sub[root];
if (tin[root] <= tin[r] && tout[root] >= tout[r]) {
int ans = depth[r];
int dis = singleDepth[r]-singleDepth[root];
ans += kthMin(r, dis);
if (ans >= 5e14) cout << "oo" << "\n";
else cout << ans << endl;
}
else cout << "escaped" << endl;
}
}
signed main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t = 1;
// cin >> t;
while (t--) {
sol();
}
return 0;
}
