#include <bits/stdc++.h>
#define respagold ios_base::sync_with_stdio(0), cin.tie(0);
#define ll long long
#define int long long
#define int2 __int128_t
#define FOR( i, x, n, d ) for( int i = x; i <= n; i += d )
#define FORR( i, x, n, d ) for( int i = x; i >= n; i -= d )
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x.size())
#define pb push_back
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define pii pair <int, int>
#define mkp make_pair
using namespace std;
const int N = 3e5 + 123;
const int inf = 2e18;
const int MOD1 = 1e9 + 7;
const int MOD = 998244353;
const int P = 6547;
int a[N], b[N], n, m, q, x, y, z, w[N], ans[N], s, e;
vector <int> shop;
pii edge[N];
mt19937 rng( chrono::steady_clock::now().time_since_epoch().count());
int rand( int l, int r )
{
uniform_int_distribution <int> uid( l, r );
return uid( rng );
}
vector <pii> g[N];
int tin[N], tout[N], up[N][21], tim, d[N];
void dfs( int v, int p = 0 )
{
up[v][0] = p;
FOR( i, 1, 20, 1 ) up[v][i] = up[up[v][i - 1]][i - 1];
tin[v] = ++ tim;
for( auto to : g[v] ) if( to.F != p ) d[to.F] = d[v] + to.S, dfs( to.F, v );
tout[v] = tim;
}
bool upper( int v, int u ) { return ( tin[v] <= tin[u] && tout[u] <= tout[v] );}
int lca( int v, int u )
{
if( upper(v, u) ) return v;
if( upper(u, v) ) return u;
FORR( i, 20, 0, 1 ) if( up[v][i] && !upper( up[v][i], u )) v = up[v][i];
return up[v][0];
}
int dist( int v, int u )
{
return d[u] + d[v] - 2 * d[lca( v, u )];
}
bool check( int y, int v, int u )
{
if( upper( v, y ) && upper( u, y ) ) return 1;
return 0;
}
void solve()
{
cin >> n >> s >> q >> e;
FOR( i, 1, n - 1, 1 )
{
cin >> x >> y >> z;
edge[i] = { x, y };
g[x].pb({ y, z });
g[y].pb({ x, z });
}
FOR( i, 1, s, 1 )
{
cin >> x;
shop.pb(x);
}
dfs(1);
FOR( i, 1, q, 1 )
{
cin >> x >> y;
int v, u; tie( v, u ) = edge[x];
if( upper( e, y ) && !check( e, v, u ) && check( y, v, u ) ) {}
else if( upper( y, e ) && check( e, v, u ) && !check( y, v, u ) ) {}
else if( ( check( y, v, u ) || check( e, v, u ) ) && !check( lca( e, y ), v, u ) ) {}
else
{
cout << "escaped\n";
continue;
}
if( s == n )
{
cout << "0\n";
continue;
}
int dis = inf;
for( auto sh : shop )
{
if( upper( sh, y ) && !check( sh, v, u ) && check( y, v, u ) ) continue;
else if( upper( y, sh ) && check( sh, v, u ) && !check( y, v, u ) ) continue;
else if( ( check( y, v, u ) || check( sh, v, u ) ) && !check( lca( sh, y ), v, u ) ) continue;
dis = min( dis, dist( sh, y ));
}
if( dis == inf ) cout << "oo\n";
else cout << dis << '\n';
}
}
signed main()
{
// freopen("connect.in", "r", stdin);
// freopen("connect.out", "w", stdout);
respagold
int test = 1;
if( !test ) cin >> test;
while( test -- )
{
solve();
}
}
// solved by KluydQ
