#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
using namespace std;
const int N = 1e5 + 5;
const long long oo = 1e18;
vector <pair <int, int>> adj[N];
pair <int, int> edge[N];
long long dp[20][N];
long long mindis[N];
long long dis[N];
long long val[N];
int lca[20][N];
int h[N];
int n,s,q,t;
bool store[N];
void dfs(int u, int p)
{
lca[0][u] = p;
mindis[u] = (store[u]) ? dis[u] : oo;
for (pair <int, int> to : adj[u])
{
int v = to.fi;
int w = to.se;
if (v == p)
continue;
h[v] = h[u] + 1;
dis[v] = dis[u] + w;
dfs(v, u);
mindis[u] = min(mindis[u], mindis[v]);
}
val[u] = mindis[u] - 2 * dis[u];
}
void build()
{
for (int i = 1; i <= n; i++)
{
int p = lca[0][i];
dp[0][i] = (p < 0) ? oo : val[p];
}
for (int j = 1; j < 20; j++)
for (int i = 1; i <= n; i++)
{
int p = lca[j - 1][i];
if (p < 0)
lca[j][i] = p, dp[j][i] = oo;
else
lca[j][i] = lca[j - 1][p], dp[j][i] = min(dp[j - 1][p], dp[j - 1][i]);
}
}
pair <long long, int> jump(int u, int step)
{
if (step < 0)
return mp(oo, -1);
long long res = val[u];
for (int i = 0; u > 0 && i < 20; i++) if ((step >> i) & 1)
{
res = min(res, dp[i][u]);
u = lca[i][u];
}
return mp(res, u);
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
//freopen("file.inp","r",stdin);
cin >> n >> s >> q >> t;
for (int i = 1; i < n; i++)
{
int u,v,w;
cin >> u >> v >> w;
adj[u].push_back(mp(v, w));
adj[v].push_back(mp(u, w));
edge[i] = mp(u, v);
}
for (int i = 1; i <= s; i++)
{
int x;
cin >> x;
store[x]= true;
}
dfs(t, -1);
build();
while (q--)
{
int id,cur;
cin >> id >> cur;
int u = edge[id].fi;
int v = edge[id].se;
if (h[u] > h[v])
swap(u, v);
pair <long long, int> res = jump(cur, h[cur] - h[v]);
if (res.se != v)
cout << "escaped\n";
else if (res.fi > (int) 1e15)
cout << "oo\n";
else
cout << res.fi + dis[cur] << "\n";
}
return 0;
}
