#include <bits/stdc++.h> using namespace std; #define ll long long #define ld long double #define lll __ll128 #define sza(x) ((ll)x.size()) #define all(a) (a).begin(), (a).end() #define pb push_back #define pll pair<ll,ll> #ifdef DEBUG #include "helper.h" #else #define dbg(...) #endif #define log(a) 63-__builtin_clzll(a) const ll INF=1e18; const ll MOD=1e9+7; void solve() { int n,s,q,e; cin>>n>>s>>q>>e; e--; vector<vector<pair<int,ll>>> edges(n); vector<pair<int,int>> all_edges; set<int> shops; for(int i=0;i<n-1;i++){ int a,b; ll c; cin>>a>>b>>c; a--,b--; all_edges.push_back({a,b}); edges[a].push_back({b,c}); edges[b].push_back({a,c}); } for(int i=0;i<s;i++){ int a; cin>>a; a--; shops.insert(a); } int LOG=__lg(n); vector<vector<pair<int,ll>>> bj(n,vector<pair<int,ll>>(LOG+1,{-1,LLONG_MAX})); vector<int> depth(n); vector<ll> cost(n); vector<ll> dp(n,LLONG_MAX); dbg(dp); dbg(edges); auto build=[&](auto && build, int u,int p,int _depth,ll _cost ) -> void { cost[u]=_cost; depth[u]=_depth; bj[u][0].first=p; if(shops.contains(u)){ dp[u]=0; } // dbg(u,p); for(auto nei:edges[u]){ if(nei.first==p)continue; build(build,nei.first,u,_depth+1,_cost+nei.second); if(dp[nei.first]!=LLONG_MAX) dp[u]=min(dp[u],nei.second+dp[nei.first]); } }; build(build,e,-1,0,0); dbg(1); for(int i=0;i<n;i++){ bj[i][0].second=min(-cost[bj[i][0].first]+dp[bj[i][0].first],-cost[i]+dp[i]); } for(int log=1;log<=LOG;log++){ for(int i=0;i<n;i++){ auto [v,cost]=bj[i][log-1]; if(v!=-1){ bj[i][log].first=bj[v][log-1].first; bj[i][log].second=min(bj[v][log-1].second,bj[i][log-1].second); } } } auto get_ans=[&](int v,int num) -> pair<int,ll> { int curr=v; ll curr_cost=-cost[v]+dp[v]; for(int i=0;i<=LOG;i++){ if(num&(1<<i)){ curr_cost=min(curr_cost,bj[curr][i].second); curr=bj[curr][i].first; } if(curr==-1)return {-1,LLONG_MAX};; } return {curr,curr_cost+cost[v]}; }; while(q--){ int index; int v; cin>>index>>v; index--,v--; auto [_p,_q]=all_edges[index]; dbg(v); if(depth[_q]<depth[_p])swap(_p,_q); dbg(get_ans(v,-depth[_q]+depth[v]),depth[_q]-depth[v]); if(get_ans(v,-depth[_q]+depth[v]).first!=_q){ cout<<"escaped"<<endl; }else{ auto [_v,ans]=get_ans(v,-depth[_q]+depth[v]); if(ans==LLONG_MAX){ cout<<"oo"<<endl; }else{ cout<<ans<<endl; } } } } int32_t main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); // freopen("cbarn2.in","r",stdin); // freopen("cbarn2.out","w",stdout); // cout<<1<<endl; // dbg(deals); // ll t; // cin>>t; // while(t--) solve(); }