#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vi = vector<int>;
using vvi = vector<vi>;
using vb = vector<bool>;
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pb push_back
const ll inf = 1e15;
void setIO()
{
fast;
}
int n = 1e5 + 5,s,q,root;
vi in(n),out(n),num(n);
vl magic(n,inf),dist(n);
vvl anc(n,vl(21)),dp(n,vl(21));
vvvl adj(n);
vb shop(n);
int t;
void dfs(int u,int p,ll wt)
{
if (p != -1)dist[u] = dist[p] + wt,num[u] = num[p] + 1;
in[u] = t++;
if (shop[u])magic[u] = dist[u];
for (auto x:adj[u]){
int v = x[0];
ll w = x[1];
if (v == p)continue;
dfs(v,u,w);
magic[u] = min(magic[u],magic[v]);
}
out[u] = t++;
}
bool is_ancestor(int u,int v)
{
return in[u] <= in[v] && out[u] >= out[v];
}
void dfs2(int u,int p)
{
anc[u][0] = p;
dp[u][0] = magic[u];
for (int i = 1;i<=20;i++){
anc[u][i] = anc[anc[u][i - 1]][i - 1];
dp[u][i] = min(dp[u][i - 1],dp[anc[u][i - 1]][i - 1]);
}
for (auto x:adj[u]){
int v = x[0];
if (v == p)continue;
dfs2(v,u);
}
}
int main()
{
setIO();
cin>>n>>s>>q>>root;
vvi edges;
for (int i = 1;i<n;i++){
int u,v,w;
cin>>u>>v>>w;
adj[u].pb({v,w});
adj[v].pb({u,w});
edges.pb({u,v});
}
for (int i = 1;i<=s;i++){
int x;
cin>>x;
shop[x] = 1;
}
dfs(root,-1,0);
for (int i = 1;i<=n;i++)if (magic[i] < inf)magic[i] += -2 * dist[i];
dfs2(root,root);
while (q--){
int pos,u;
cin>>pos>>u;
int child = edges[pos - 1][0],par = edges[pos - 1][1];
if (in[child] < in[par])swap(child,par);
if (!is_ancestor(child,u))cout<<"escaped"<<'\n';
else {
//now find min of magic[v] for all v on the path from u to child
int distance = - num[child] + num[u] + 1;
int node = u;
ll val = inf;
for (int i = 0;i<=20;i++){
if (distance&(1<<i)){
val = min(val,dp[u][i]);
u = anc[u][i];
}
}
if (val >= inf)cout<<"oo"<<'\n';
else cout<<dist[node] + val<<'\n';
}
}
return 0;
}
