#include <bits/stdc++.h>
using namespace std;
int n, s, q, e;
int const N = 100005;
vector<pair<int, int>> g[N];
vector <int> et;
pair<int, int> eti[N];
vector<int> shops;
map<int, int> isshop;
pair<int, int> roads[N];
void fet(int u, int p)
{
et.push_back(u);
eti[u]={et.size()-1, 0};
for(auto i: g[u])
{
if(i.first == p)continue;
fet(i.first, u);
}
et.push_back(u);
eti[u]={eti[u].first, et.size()-1};
}
long long closest[N];
int const LOG = log2(N) + 2;
int par[N][LOG];
long long dist[N];
void clo(int u, int p)
{
long long rez=1e18+5;
closest[u]=1e18+5;
par[u][0] = p;
for(int i = 1; i < LOG; i++)
{
par[u][i]=par[par[u][i-1]][i-1];
}
for(auto i: g[u])
{
if(i.first == p)continue;
dist[i.first] =dist[u]+i.second;
clo(i.first, u);
//if(rez==-1) rez = closest[i.first]+i.second;
rez=min(rez, closest[i.first]+i.second);
}
if(isshop[u])
{
closest[u]=0;
}
else
{
closest[u]=rez;
}
}
long long best[N][LOG];
void dfs(int u, int p)
{
best[u][0] = dist[u] - dist[p] + closest[p];
for(int i = 1; i < LOG; i++)
{
int jump = par[u][i-1];
best[u][i] = min(best[u][i-1], dist[u]-dist[jump]+best[jump][i-1]);
}
for(auto i: g[u])
{
if(i.first==p)continue;
dfs(i.first, u);
}
}
long long get_best(int r, int u)
{
long long cur = closest[r], di = 0;
for(int i = LOG-1; i >= 0; i--)
{
int jump = par[r][i];
if(eti[jump].first <= eti[u].first && eti[u].second <= eti[jump].second)
{
continue;
}
cur = min(cur, di+best[r][i]);
di+=dist[r]-dist[jump];
r=jump;
}
return cur;
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> s >> q >> e;
for(int i = 0; i < n-1; i++)
{
int a, b, w; cin >> a >> b >> w;
g[a].push_back({b, w});
g[b].push_back({a, w});
roads[i+1]={a, b};
}
for(int i =0; i < s; i++)
{
int x; cin >> x;
shops.push_back(x);
isshop[x]=1;
}
fet(e, e);
clo(e, e);
dfs(e, e);
while(q--)
{
int i, r; cin >> i >> r;
if(eti[roads[i].first].first <= eti[r].first && eti[roads[i].second].first <= eti[r].first && eti[roads[i].first].second >= eti[r].second && eti[roads[i].second].second >= eti[r].second)
{
int x = roads[i].first;
if(dist[roads[i].first] > dist[roads[i].second])
{
x = roads[i].second;
}
long long rez = get_best(r, x);
if(rez==1e18+5)
{
cout << "oo\n";
}
else
{
cout << rez << "\n";
}
}
else
{
cout << "escaped\n";
}
}
return 0;
}
