#include <bits/stdc++.h>
#define task "VALLEY"
#define ll long long
#define ld long double
#define fi first
#define se second
#define pb push_back
using namespace std;
const int MAXN = 1e5 + 5;
const ll INF = 1e18 + 5;
const int LOGN = 19;
int n, s, q, e;
vector<pair<int, int>> Adj[MAXN];
bool ishop[MAXN];
struct TEdge
{
int u, v, w;
}es[MAXN];
void Input()
{
cin >> n >> s >> q >> e;
for (int i = 1; i < n; i++)
{
int u, v, w;
cin >> u >> v >> w;
es[i] = {u, v, w};
Adj[u].pb({v, w});
Adj[v].pb({u, w});
}
for (int i = 1; i <= s; i++)
{
int c;
cin >> c;
ishop[c] = 1;
}
}
ll dp[MAXN];
int P[MAXN][LOGN];
ll M[MAXN][LOGN], d[MAXN];
int deg[MAXN];
void DFS(int u, int par)
{
if (!ishop[u])
dp[u] = INF;
for (auto v : Adj[u])
{
if (v.fi == par)
continue;
d[v.fi] = v.se + d[u];
P[v.fi][0] = u;
deg[v.fi] = deg[u] + 1;
DFS(v.fi, u);
dp[u] = min(dp[u], dp[v.fi] + v.se);
}
}
void DFS2(int u, int par)
{
for (auto v : Adj[u])
{
if (v.fi != par)
{
M[v.fi][0] = dp[u] - d[u];
DFS2(v.fi, u);
}
}
}
bool LCAdinh(int u, int v)
{
for (int i = LOGN - 1; i >= 0; i--)
{
if (deg[P[u][i]] >= deg[v])
u = P[u][i];
}
return u == v;
}
ll LCAcanh(int u, int v)
{
ll res = dp[u] - d[u];
for (int i = LOGN - 1; i >= 0; i--)
{
if (deg[P[u][i]] >= deg[v])
{
res = min(res, M[u][i]);
u = P[u][i];
}
}
//res = min(res, dp[v]);
return res;
}
void Solve()
{
deg[e] = 1;
DFS(e, 0);
DFS2(e, 0);
for (int i = 1; i < LOGN; i++)
for (int j = 1; j <= n; j++)
{
P[j][i] = P[P[j][i - 1]][i - 1];
M[j][i] = min(M[j][i - 1], M[P[j][i - 1]][i - 1]);
}
while (q-- > 0)
{
int id, r;
cin >> id >> r;
if (P[es[id].u][0] == es[id].v)
swap(es[id].u, es[id].v);
if (!LCAdinh(r, es[id].v))
{
cout << "escaped\n";
continue;
}
ll ans = LCAcanh(r, es[id].v);
if (ans + d[r] == INF)
cout << "oo\n";
else
cout << ans + d[r] << '\n';
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//freopen(task".INP" , "r" , stdin);
//freopen(taskname".OUT" , "w" , stdout);
Input();
Solve();
return 0;
}
