#include<bits/stdc++.h>
#define ll long long
#define ld long double
#define pb push_back
#define pii pair<int, int>
#define fi first
#define se second
#define bit(x, i) ((x >> (i)) & 1)
#define SZ(x) ((int)(x.size()))
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define task "LANDSLIDE"
using namespace std;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { assert(l <= r); return uniform_int_distribution<ll>(l, r)(rd); }
const int MAXn = 1e5 + 5;
const int MOD = 1e9 + 7;
const int BASE = 3137;
const int BL = 320;
const ll oo = (long long)(1e18);
int n,S,Q,H,I,R;
ll ans=MOD;
bool lt[MAXn],issafe=0,isok=0;
struct edge{
int v;
ll w;
int id;
edge(int vv=0,ll ww=0,int idd=0):v(vv),w(ww),id(idd){};
};
vector<edge>adj[MAXn];
void dfs(int u,int par,ll sumw){
if(u==H){issafe=1;return;}
if(lt[u]){isok=1;ans=min(ans,sumw);}
for(edge x:adj[u]){
if(x.v==par)continue;
if(x.id==I)continue;
dfs(x.v,u,sumw+x.w);
}
}
void solve() {
cin>>n>>S>>Q>>H;
FOR(i,1,n-1){
int u,v;ll w;cin>>u>>v>>w;
adj[u].pb(edge(v,w,i));
adj[v].pb(edge(u,w,i));
}
FOR(i,1,S){int C;cin>>C;lt[C]=1;}
while(Q--){
issafe=0;isok=0;ans=oo;
cin>>I>>R;
dfs(R,0,0LL);
if(issafe)cout<<"escaped\n";
else{
if(isok){cout<<ans<<'\n';}
else cout<<"oo\n";
}
}
}
int32_t main() {
if (fopen(task".inp", "r")) { freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); }
ios::sync_with_stdio(0); cin.tie(0);
int ntest = 1; //cin >> ntest;
while (ntest--) solve();
cerr << "\n\n" << 1.0 * clock() / CLOCKS_PER_SEC << "s ";
}
