#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pii>
#define vll vector<pll>
#define FOR(i,N) for(i=0;i<(N);++i)
#define FORe(i,N) for(i=1;i<=(N);++i)
#define FORr(i,a,b) for(i=(a);i<(b);++i)
#define FORrev(i,N) for(i=(N);i>=0;--i)
#define F0R(i,N) for(int i=0;i<(N);++i)
#define F0Re(i,N) for(int i=1;i<=(N);++i)
#define F0Rr(i,a,b) for(ll i=(a);i<(b);++i)
#define F0Rrev(i,N) for(int i=(N);i>=0;--i)
#define all(v) (v).begin(),(v).end()
#define dbgLine cerr<<" LINE : "<<__LINE__<<"\n"
#define ldd long double
using namespace std;
const int Alp = 26;
const int __PRECISION = 9;
const int inf = 1e9 + 8;
const ldd PI = acos(-1);
const ldd EPS = 1e-7;
const ll MOD = 1e9 + 7;
const ll MAXN = 1e5 + 5;
const ll ROOTN = 320;
const ll LOGN = 18;
const ll INF = 1e18 + 1022;
int N, Q, E, S, CLK, xt[MAXN], nt[MAXN], par[LOGN][MAXN], depcnt[MAXN];
ll dp[MAXN], sparse[LOGN][MAXN], dep[MAXN];
bool shop[MAXN];
vector<pair<int, ll>> g[MAXN];
vector<pair<pii, ll>> edge_list;
ll dfs(int a, int pp)
{
nt[a] = CLK++;
par[0][a] = pp;
for(pair<int, ll> b : g[a])
if(b.ff != pp)
{
dep[b.ff] = b.ss + dep[a];
depcnt[b.ff] = 1 + dep[a];
dp[a] = min(dp[a], dfs(b.ff, a) + b.ss);
}
if(shop[a])
dp[a] = 0;
for(pair<int, ll> b : g[a])
if(b.ff != pp)
{
// cerr<<"sparse[0]["<<b.ff<<"] = "<<min(sparse[0][b.ff], b.ss + dp[a])<<'\n';
sparse[0][b.ff] = min(sparse[0][b.ff], b.ss + dp[a]);
}
xt[a] = CLK++;
return dp[a];
}
inline void init_sparse_table()
{
F0Re(i, LOGN-1)
F0Re(a, N)
par[i][a] = (par[i-1][a] == -1) ? -1 : par[i-1][par[i-1][a]],
sparse[i][a] = min(sparse[i-1][a],(((par[i-1][a]==-1) ? INF : (sparse[i-1][par[i-1][a]] + dep[a] - dep[par[i-1][a]]))));
}
// inline void dbg_dp()
// {
// F0Re(i, N)
// cout<<"dp["<<i<<"] = "<<dp[i]<<'\n';
// }
inline void pre_process()
{
CLK = 0;
dep[E] = depcnt[E] = 0;
F0Re(i, N)
dp[i] = INF;
F0R(i, LOGN)
F0Re(a, N)
sparse[i][a] = INF;
dfs(E, -1);
// dbg_dp();
init_sparse_table();
}
inline void query(int e, int a)
{
int u = (depcnt[edge_list[e].ff.ff] > depcnt[edge_list[e].ff.ss]) ? edge_list[e].ff.ff : edge_list[e].ff.ss;
if(!(nt[u] <= nt[a] and xt[u] >= xt[a]))
{
cout<<"escaped\n";
return;
}
int b = a;
ll ans = dp[a];
F0Rrev(i, LOGN-1)
{
if(par[i][b] == -1 or depcnt[par[i][b]] < depcnt[u])
continue;
ans = min(ans, sparse[i][b] + dep[a] - dep[b]);
// cerr<<"considering "<<par[i][b]<<" and sparse["<<i<<"]["<<b<<"] = "<<sparse[i][b]<<'\n';
b = par[i][b];
}
if(ans == INF)
cout<<"oo\n";
else
cout<<ans<<'\n';
}
signed main()
{
/*
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
*/
int j, k;
ll len;
cin>>N>>S>>Q>>E;
F0R(i, N-1)
{
cin>>j>>k>>len;
edge_list.pb(mp(mp(j, k), len));
g[j].pb(mp(k,len));
g[k].pb(mp(j,len));
}
F0Re(i, N)
shop[i] = false;
F0Re(i, S)
{
cin>>j;
shop[j] = true;
}
// F0Re(i, N)
// cerr<<shop[i]<<' ';
// cerr<<'\n';
pre_process();
while(Q--)
{
cin>>j>>k;
query(j-1, k);
}
return 0;
}
/*
5 2 3 1
1 2 3
1 3 2
3 4 1
3 5 2
2 4
2 2
2 5
4 5
10 2 5 4
7 2 3
4 8 3
9 10 1
6 7 3
9 2 3
10 1 2
8 2 2
5 2 1
3 8 2
8
7
2 1
1 5
8 4
6 2
7 7
*/
