#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define pb(e) push_back(e)
#define sv(a) sort(a.begin(),a.end())
#define sa(a,n) sort(a,a+n)
#define mp(a,b) make_pair(a,b)
#define vf first
#define vs second
#define ar array
#define all(x) x.begin(),x.end()
//const int inf = 0x3f3f3f3f;
const int mod = 1000000007;
const double PI=3.14159265358979323846264338327950288419716939937510582097494459230;
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
bool remender(ll a , ll b){return a%b;}
//freopen("problemname.in", "r", stdin);
//freopen("problemname.out", "w", stdout);
const int N = 100002,L=20;
vector<pair<int,ll>> adj[N];
bool shop[N];
int timer,tin[N],tout[N],up[N][L];
ll sum[N][L],shop_dis[N][L],subtree_dis[N];
ll inf = 100000000000005;
void init(int node , int par){
subtree_dis[node] = inf;
if(shop[node])subtree_dis[node] = 0;
for(auto i : adj[node]){
if(i.vf != par){
init(i.vf , node);
subtree_dis[node] = min(subtree_dis[node] , subtree_dis[i.vf]+i.vs);
}
}
}
void dfs(int node , int par , int weight){
up[node][0] = par;
tin[node] = timer++;
sum[node][0] = weight;
shop_dis[node][0] = subtree_dis[par]+sum[node][0];
for(int i = 1; i < L; i++){
up[node][i] = up[up[node][i-1]][i-1];
shop_dis[node][i] = min(shop_dis[node][i-1],shop_dis[up[node][i-1]][i-1]+sum[node][i-1]);
sum[node][i] = sum[node][i-1] + sum[up[node][i-1]][i-1];
}
for(auto i : adj[node]){
if(i.vf != par){
dfs(i.vf , node , i.vs);
}
}
tout[node] = timer++;
}
bool is_lca(int x , int y){
return tin[x] <= tin[y] && tout[x] >= tout[y];
}
int find(int x , int y){
if(is_lca(x,y))return x;
if(is_lca(y,x))return y;
for(int i = L - 1; i >= 0; i--){
if(!is_lca(up[x][i],y))x = up[x][i];
}
return up[x][0];
}
void solve(){
int n;
cin >> n;
int m;
cin >> m;
int q;
cin >> q;
int root;
cin >> root;
vector<pair<int,int>> edges;
for(int i = 0; i < n - 1; i++){
int u , v , w;
cin >> u >> v >> w;
adj[u].pb(mp(v,w));
adj[v].pb(mp(u,w));
edges.pb(mp(u,v));
}
for(int i = 0; i < m; i++){
int x;
cin >> x;
shop[x] = 1;
}
init(root,root);
timer = 0;
dfs(root,root,0);
while(q--){
int index , start;
cin >> index >> start;
index--;
int a = edges[index].vf , b = edges[index].vs;
if(!is_lca(a,b)){
swap(a,b);
}
if(is_lca(b,start)){
ll ans = subtree_dis[start];
for(int i = L-1; i >= 0; i--){
if(is_lca(b,up[start][i])){
ans = min(ans , shop_dis[start][i]);
start = up[start][i];
}
}
if(ans >= inf){
cout << "oo\n";
}
else cout << ans << '\n';
}
else {
cout << "escaped\n";
}
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// int t;cin>>t;
// while(t--){
solve();
//}
return 0;
}
