#include <bits/stdc++.h>
using namespace std;
//#define DEBUG
void setIO(const string &name) {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin.exceptions(istream::failbit);
#ifdef LOCAL
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
freopen((name + ".out").c_str(), "w", stderr);
#endif
}
const int inf = 0x3f3f3f3f, mod = 1e9 + 7, maxn = 1e5 + 5, maxs = 20;
const long long INFL = 0x3f3f3f3f3f3f3f3f;
vector<pair<int, int>> adj[maxn];
pair<int, int> edge[maxn];
int up[maxn][maxs], depth[maxn], n, tin[maxn], tout[maxn], t;
long long dist[maxn], dp[maxn], val[maxn][maxs];
bool shop[maxn];
long long jmp(int x, int d) {
long long res = INFL;
for (int i = 0; i < maxs; i++) {
if ((d >> i) & 1) {
res = min(res, val[x][i]);
x = up[x][i];
}
}
return res;
}
void dfs(int c = 0, int p = -1, int de = 0, long long di = 0) {
up[c][0] = p;
depth[c] = de;
dist[c] = di;
tin[c] = t++;
if (shop[c]) {
dp[c] = -di;
}
for (auto &i : adj[c]) {
if (i.first != p) {
dfs(i.first, c, de + 1, di + i.second);
if (dp[i.first] != INFL) {
dp[c] = min(dp[c], dp[i.first] + 2 * i.second);
}
}
}
tout[c] = t;
val[c][0] = dp[c];
}
void build() {
for (int i = 1; i < maxs; ++i) {
for (int j = 0; j < n; ++j) {
if (up[j][i - 1] == -1) {
up[j][i] = -1;
} else {
val[j][i] = min(val[j][i - 1], val[up[j][i - 1]][i - 1]);
up[j][i] = up[up[j][i - 1]][i - 1];
}
}
}
}
int main() {
setIO("2");
memset(dp, 0x3f, sizeof(dp));
memset(dist, 0x3f, sizeof(dist));
int s, q, e;
cin >> n >> s >> q >> e;
--e;
for (int i = 0; i < n - 1; ++i) {
int a, b, c;
cin >> a >> b >> c;
--a, --b;
adj[a].emplace_back(b, c);
adj[b].emplace_back(a, c);
edge[i] = {a, b};
}
for (int i = 0; i < s; ++i) {
int c;
cin >> c;
--c;
shop[c] = true;
}
memset(val, 0x3f, sizeof(val));
dfs(e);
build();
while (q--) {
int road, u;
cin >> road >> u;
--road, --u;
int l = (depth[edge[road].first] > depth[edge[road].second] ? edge[road].first : edge[road].second);
if (!(tin[u] >= tin[l] && tout[u] <= tout[l])) { // u is not in subtree of l
cout << "escaped" << "\n";
continue;
}
long long sol = jmp(u, depth[u] - depth[l] + 1);
if (sol == INFL) {
cout << "oo" << "\n";
} else {
cout << sol + dist[u] << "\n";
}
}
return 0;
}
