#include <bits/stdc++.h>
#define pii pair<int, int>
#define fi first
#define se second
#define ll long long
using namespace std;
int n, s, q, e, bc;
const int N = 1e5+5;
const ll M = 1e17;
bool sh[N];
pii cel[N];
vector<pii> graf[N];
ll dfs(int v, int p)
{
if(v == e)
return -1;
ll ret = M;
for(auto x: graf[v])
if(x.fi != p &&
cel[bc] != make_pair(v, x.fi) &&
cel[bc] != make_pair(x.fi, v))
{
ll r = dfs(x.fi, v);
if(r == -1) ret = -1;
ret = min(ret, r+x.se);
}
if(sh[v]) ret = min(ret, 0ll);
return ret;
}
int main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n >> s >> q >> e;
for(int i=1; i<n; i++)
{
int u, v, w; cin >> u >> v >> w;
cel[i] = {u, v};
graf[u].push_back({v, w});
graf[v].push_back({u, w});
}
for(int i=0; i<s; i++)
{
int c; cin >> c;
sh[c] = 1;
}
while(q--)
{
int r; cin >> bc >> r;
ll d = dfs(r, 0);
if(d == -1) cout << "escaped\n";
else if(d >= M) cout << "oo\n";
else cout << d << '\n';
}
return 0;
}
