#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int mod = 1000 * 1000 * 1000 + 7;
const int INF = 1000 * 1000 * 1000;
const ll LINF = (ll)INF * INF;
#ifdef DEBUG
#define dbg(x) cout << #x << " = " << (x) << endl << flush;
#define dbgr(s, f) { cout << #s << ": "; for (auto _ = (s); _ != (f); _++) cout << *_ << ' '; cout << endl << flush; }
#else
#define dbg(x) ;
#define dbgr(s, f) ;
#endif
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define fast_io ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define msub(a, b) ((mod + ((ll)(a) - (b)) % mod) % mod)
#define mdiv(a, b) ((ll)(a) * poww((b), mod - 2) % mod)
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define mp make_pair
#define fr first
#define sc second
#define endl '\n'
struct QR
{
int e, v, ind;
};
#define MAXN 100100
int n, sp, q, E;
vector<int> adj[MAXN];
bool shop[MAXN];
int efrom[MAXN], eto[MAXN], ew[MAXN];
int sttime[MAXN], fntime[MAXN], timer;
vector<QR> qr[MAXN];
ll dist[MAXN];
ll ans[MAXN];
int h[MAXN];
void fr_dfs(int v, int par = -1)
{
sttime[v] = timer++;
for (int e : adj[v])
{
int u = efrom[e] ^ eto[e] ^ v;
if (u == par)
continue;
dist[timer] = dist[sttime[v]] + ew[e];
h[u] = h[v] + 1;
fr_dfs(u, v);
}
fntime[v] = timer;
}
inline bool insub(int v, int u)
{
return (sttime[v] <= sttime[u] && sttime[u] < fntime[v]);
}
ll seg[4 * MAXN];
ll lazy[4 * MAXN];
void build(int v = 1, int l = 0, int r = n - 1)
{
if (l == r)
{
seg[v] = dist[l];
return;
}
int mid = (r + l) / 2;
build(2 * v, l, mid);
build(2 * v + 1, mid + 1, r);
seg[v] = min(seg[2 * v], seg[2 * v + 1]);
}
void pushdown(int v)
{
if (!lazy[v])
return;
lazy[2 * v] += lazy[v];
lazy[2 * v + 1] += lazy[v];
seg[2 * v] += lazy[v];
seg[2 * v + 1] += lazy[v];
lazy[v] = 0;
}
void add(int L, int R, ll x, int v = 1, int l = 0, int r = n - 1)
{
if (l > R || r < L)
return;
if (l >= L && r <= R)
{
lazy[v] += x;
seg[v] += x;
return;
}
int mid = (r + l) / 2;
pushdown(v);
add(L, R, x, 2 * v, l, mid);
add(L, R, x, 2 * v + 1, mid + 1, r);
seg[v] = min(seg[2 * v], seg[2 * v + 1]);
}
ll rmin(int L, int R, int v = 1, int l = 0, int r = n - 1)
{
if (l > R || r < L)
return LINF;
if (l >= L && r <= R)
return seg[v];
int mid = (r + l) / 2;
pushdown(v);
return min(rmin(L, R, 2 * v, l, mid), rmin(L, R, 2 * v + 1, mid + 1, r));
}
void sc_dfs(int v, int par)
{
for (QR q : qr[v])
{
int u = efrom[q.e];
if (h[u] < h[eto[q.e]])
u = eto[q.e];
/*
if (q.ind == 0)
{
dbg(v);
dbg(u);
dbgr(seg, seg + n);
dbg(efrom[q.e]);
dbg(eto[q.e]);
dbgr(h + 1, h + n + 1);
}
*/
if (!(insub(u, v) ^ insub(u, E)))
{
ans[q.ind] = -1; // escaped
continue;
}
if (insub(u, v))
{
ans[q.ind] = rmin(sttime[u], fntime[u] - 1);
}
else
{
ans[q.ind] = min(rmin(0, sttime[u] - 1), rmin(fntime[u], n - 1));
}
}
for (int e : adj[v])
{
int u = efrom[e] ^ eto[e] ^ v;
if (u == par)
continue;
ll w = ew[e];
add(0, n - 1, w);
add(sttime[u], fntime[u] - 1, -2 * w);
sc_dfs(u, v);
add(sttime[u], fntime[u] - 1, 2 * w);
add(0, n - 1, -w);
}
}
int32_t main(void)
{
fast_io;
cin >> n >> sp >> q >> E;
FOR(i, 0, n - 1)
{
int x, y, w;
cin >> x >> y >> w;
adj[x].pb(i);
adj[y].pb(i);
efrom[i] = x;
eto[i] = y;
ew[i] = w;
}
FOR(i, 0, sp)
{
int x;
cin >> x;
shop[x] = true;
}
FOR(i, 0, q)
{
int x, y;
cin >> x >> y;
x--;
QR tmp = {x, y, i};
qr[y].pb(tmp);
}
fr_dfs(1);
FOR(i, 1, n + 1)
{
if (!shop[i])
{
dist[sttime[i]] = LINF;
}
}
/*
dbgr(dist, dist + n);
dbgr(sttime + 1, sttime + n + 1);
dbgr(fntime + 1, fntime + n + 1);
dbg("=========\n\n");
*/
build();
sc_dfs(1, -1);
FOR(i, 0, q)
{
if (ans[i] == -1)
{
cout << "escaped\n";
}
else if (ans[i] >= LINF/10)
{
cout << "oo\n";
}
else
{
cout << ans[i] << endl;
}
}
return 0;
}
