#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#pragma GCC optimize("Ofast")
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define int long long
#define lowbit(x) x&-x
const int maxn = 1e5 + 5;
const int INF = 1e18;
int n, s, q, e;
vector<pll> adj[maxn];
int succ[maxn][18], dep[maxn], ans[maxn], val[maxn][18], st[maxn];
int d[maxn];
pll edge[maxn];
void dfs(int pos, int prev){
succ[pos][0] = prev;
ans[pos] = (st[pos] ? 0 : INF);
for(int i = 1; i < 18; i++) succ[pos][i] = succ[succ[pos][i - 1]][i - 1];
for(auto [x, w] : adj[pos]){
if(x == prev) continue;
dep[x] = dep[pos] + 1;
d[x] = d[pos] + w;
dfs(x, pos);
ans[pos] = min(ans[pos], ans[x] + w);
}
}
void dfs2(int pos, int prev){
val[pos][0] = ans[succ[pos][0]] - d[succ[pos][0]];
for(int i = 1; i < 18; i++) val[pos][i] = min(val[pos][i - 1], val[succ[pos][i - 1]][i - 1]);
for(auto [x, w] : adj[pos]){
if(x == prev) continue;
dfs2(x, pos);
}
}
int lift(int b, int steps){
for(int i = 17; i >= 0; i--){
if(steps & (1 << i)) b = succ[b][i];
}
return b;
}
signed main(void){
fastio;
cin>>n>>s>>q>>e;
e--;
for(int i = 0; i < n - 1; i++){
int a, b, w;
cin>>a>>b>>w;
a--, b--;
edge[i].f = a, edge[i].s = b;
adj[a].eb(b, w);
adj[b].eb(a, w);
}
for(int i = 0; i < s; i++){
int c;
cin>>c;
st[c - 1] = 1;
}
dfs(e, e);
dfs2(e, e);
for(int i = 0; i < q; i++){
int id, r;
cin>>id>>r;
id--, r--;
auto [a, b] = edge[id];
if(dep[r] < dep[a] || dep[r] < dep[b] || lift(r, dep[r] - dep[a]) != a || lift(r, dep[r] - dep[b]) != b){
cout<<"escaped\n";
continue;
}
if(dep[a] > dep[b]) swap(a, b);
int mn = ans[r];
int dif = dep[r] - dep[b], pos = r;
for(int i = 17; i >= 0; i--){
if(dif & (1 << i)) mn = min(mn, val[pos][i] + d[r]), pos = succ[pos][i];
}
if(mn >= INF) cout<<"oo\n";
else cout<<mn<<"\n";
}
}
