#include <bits/stdc++.h>
#define int int64_t
using namespace std;
vector<vector<pair<int, int>>>graph;
vector<vector<int>>up, val;
vector<int>tin, tout, dist, lvl, shh, shop;
int timer = 0;
int l = 32;
int min(int a, int b){
if(a < b) return a;
return b;
}
void dfs(int v, int p){
tin[v] = timer++;
up[v][0] = p;
if(shop[v]) shh[v] = 0;
for(int i = 1; i<=l; ++i){
up[v][i] = up[up[v][i-1]][i-1];
}
for(auto [u, w]: graph[v]){
if(u != p){
lvl[u] = lvl[v] + 1;
dist[u] = dist[v] + w;
dfs(u, v);
shh[v] = min(shh[u] + dist[u]-dist[v], shh[v]);
assert(dist[u] - dist[v] >= 0);
}
}
tout[v] = timer++;
}
void table(int v, int p){
val[v][0] = dist[v] - dist[p] + shh[p];
for(int i = 1; i<=l; ++i){
val[v][i] = min(val[v][i-1], val[up[v][i-1]][i-1] + dist[v] - dist[up[v][i-1]]);
}
for(auto [u, w]: graph[v]) if(u != p) table(u, v);
}
int check(int u, int v){
if(tin[u] <= tin[v] && tout[u] >= tout[v]) return 1;
return 0;
}
int lca(int u, int v){
if(check(u, v)) return u;
if(check(v, u)) return v;
for(int i = l; i>=0; --i){
if(!check(up[u][i], v)) u = up[u][i];
}
return up[u][0];
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, s, q, e; cin>>n>>s>>q>>e;
--e;
vector<pair<int, int>>edges;
graph.assign(n, vector<pair<int, int>>());
up.assign(n, vector<int>(33));
val.assign(n, vector<int>(33));
tin.assign(n, 0);
tout.assign(n, 0);
dist.assign(n, 0);
lvl.assign(n, 0);
shh.assign(n, 1e18);
shop.assign(n, 0);
for(int i = 0; i<n-1; ++i){
int a, b, c; cin>>a>>b>>c;
--a; --b;
graph[a].push_back({b, c});
graph[b].push_back({a, c});
edges.push_back({a, b});
}
for(int i = 0; i<s; ++i){
int c; cin>>c;
--c;
shop[c] = 1;
}
dfs(e, e);
//for(auto u: shh) cout<<u<<" ";
//cout<<endl;
table(e, e);
/*
for(int i = 0; i<n; ++i){
for(int j = 0; j<3; ++j) cout<<val[i][j]<<" ";
cout<<endl;
}
cout<<endl;
*/
/*
for(auto [x, y]: edges) cout<<x<<" "<<y<<endl;
cout<<endl;
*/
for(int i = 0; i<q; ++i){
int j, r; cin>>j>>r;
--j; --r;
int a = edges[j].first;
int b = edges[j].second;
int cur;
if(lvl[a] > lvl[b]) cur = a;
else cur = b;
//cout<<cur<<" "<<r<<" "<<j<<endl;
if(lca(cur, r) != cur) cout<<"escaped"<<'\n';
else{
int one = shh[r];
int range = lvl[r] - lvl[cur];
int jump = r;
int two = 1e18;
for(int i = l; i>=0; --i){
if(range >= 1ll<<i){
range -= 1ll<<i;
two = val[jump][i] + dist[r] - dist[jump];
jump = up[jump][i];
//cout<<jump<<" "<<two<<endl;
}
}
if(min(one, two) < 1e18) cout<<min(one, two)<<'\n';
else cout<<"oo"<<'\n';
}
}
cout<<'\n';
}
