#include <bits/stdc++.h>
#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())
using namespace std;
template<typename U, typename V> bool maxi(U &a, V b) {
if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
if (a > b) { a = b; return 1; } return 0;
}
const int N = (int)2e5 + 9;
const int mod = (int)1e9 + 7;
void prepare(); void main_code();
int main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
const bool MULTITEST = 0; prepare();
int num_test = 1; if (MULTITEST) cin >> num_test;
while (num_test--) { main_code(); }
}
void prepare() {};
int n, s, q, e;
const int LG = 17;
int par[N][LG + 1], h[N];
long long dist[N];
int lca(int u, int v) {
if (u == v) return u;
if (h[u] < h[v]) swap(u, v);
FOD(j, LG, 0) if (h[par[u][j]] >= h[v]) u = par[u][j];
if (u == v) return u;
FOD(j, LG, 0) if (par[u][j] != par[v][j])
u = par[u][j], v = par[v][j];
return par[u][0];
}
const long long INF = (long long)1e16;
bool shop[N];
long long cshop[N], jmp[N][LG + 1], val[N];
vector<pair<int, int>> g[N];
int _timer = 0, tin[N], tout[N];
void dfs(int u, int p) {
cshop[u] = INF;
if (shop[u]) cshop[u] = dist[u];
for(int j = 1; j <= LG; ++j) {
par[u][j] = par[ par[u][j - 1] ][j - 1];
}
tin[u] = ++_timer;
for(auto j : g[u]) if (j.fi ^ p) {
int v = j.fi;
h[v] = h[u] + 1;
par[v][0] = u;
dist[v] = dist[u] + j.se;
dfs(v, u);
cshop[u] = min(cshop[u], cshop[v]);
}
tout[u] = ++_timer;
}
void dfs2(int u, int p) {
val[u] = cshop[u] - 2LL * dist[u];
if (cshop[u] == INF) val[u] = INF;
jmp[u][0] = min(val[u], val[p]);
for(int j = 1; j <= LG; ++j) {
jmp[u][j] = min(jmp[u][j - 1], jmp[par[u][j - 1]][j - 1]);
}
for(auto j : g[u]) if (j.fi ^ p) {
dfs2(j.fi, u);
}
}
ii E[N];
long long jump(int u, int p) {
long long res = INF;
for(int j = LG; j >= 0; --j) {
if (h[ par[u][j] ] < h[p]) continue ;
res = min(res, jmp[u][j]);
u = par[u][j];
}
return res;
}
void main_code() {
cin >> n >> s >> q >> e;
for(int i = 1; i < n; ++i) {
int u, v, w; cin >> u >> v >> w;
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
E[i] = _mp(u, v);
}
for(int i = 1; i <= s; ++i) {
int x; cin >> x; shop[x] = 1;
}
FOR(i, 0, n) FOR(j, 0, LG) jmp[i][j] = INF;
h[0] = -1; val[0] = INF;
dfs(e, 0); dfs2(e, 0);
while (q--) {
int i, r; cin >> i >> r;
int u = E[i].fi, v = E[i].se;
if (h[u] > h[v]) swap(u, v);
if (tin[v] <= tin[r] and tout[r] <= tout[v]) {
long long l = jump(r, v);
if (l == INF) {
cout << "oo\n";
} else {
cout << l + dist[r] << nl;
}
} else {
cout << "escaped\n";
}
}
}
/* Let the river flows naturally */
