#include <bits/stdc++.h>
#ifdef LOCAL
#include "/home/trcmai/code/tools.h"
#define debug(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << endl;
#else
#define debug(x...)
#endif
using namespace std;
#define all(a) a.begin(), a.end()
#define ll long long
#define endl '\n'
const int N = 1e6 + 6, LOG = 27, MOD = 1e9 + 7;
const ll INF = 1e18;
int n,s,q,root;
vector<pair<int,ll>>g[N];
bool shop[N];
ll dep[N],mn[N],dp[N][LOG];
int h[N],tin[N],tout[N],up[N][LOG];
signed main() {
cin.tie(0)->sync_with_stdio(0);
auto solver=[&](){
cin>>n>>s>>q>>root;
vector<tuple<int,int,ll>>edge(n + 1);
for(int i = 1;i < n;++i){
int u,v; ll w;
cin>>u>>v>>w;
g[u].emplace_back(v,w);
g[v].emplace_back(u,w);
edge[i] = {u,v,w};
}
fill(mn + 1,mn + n + 1,INF);
for(int i = 1;i <= s;++i){
int ver; cin>>ver;
mn[ver] = 0;
}
auto dfs1=[&](auto &&self,int u,int p)->void{
for(auto &[v,w] : g[u]){
if(v == p) continue;
self(self,v,u);
mn[u] = min(mn[u],mn[v] + w);
}
};
int timer = 0;
auto dfs2=[&](auto &&self,int u,int p)->void{
tin[u] = ++timer;
for(auto &[v,w] : g[u]){
if(v == p) continue;
dep[v] = dep[u] + w;
h[v] = h[u] + 1;
up[v][0] = u;
dp[v][0] = mn[u] - dep[u];
for(int i = 1;i < LOG;++i){
up[v][i] = up[up[v][i-1]][i-1];
dp[v][i] = min(dp[v][i-1],dp[up[v][i-1]][i-1]);
}
self(self,v,u);
}
tout[u] = timer;
};
auto lift=[&](int u,int anc){
int k = h[u] - h[anc];
ll res = mn[u] - dep[u];
for(int i = 0;i < LOG;++i){
if(k>>i&1){
res = min(res,dp[u][i]);
u = up[u][i];
}
}
return res;
};
dfs1(dfs1,root,0);
dfs2(dfs2,root,0);
while(q--){
int idx,vert; cin>>idx>>vert;
auto [u,v,w] = edge[idx];
if(v == up[u][0]) swap(u,v);
if(!(tin[v] <= tin[vert] && tout[v] >= tout[vert])){
cout<<"escaped"<<endl;
continue;
}
ll dist = lift(vert,v) + dep[vert];
if(dist >= 1e14) cout<<"oo"<<endl;
else cout<<dist<<endl;
}
};
int t = 1; // cin>>t;
while (t--) solver();
}
