#include<bits/stdc++.h>
#define fi first
#define se second
#define int long long
using namespace std;
using ll = long long;
using ii = pair<int, int>;
using aa = array<int,3>;
const int N = 1e5+5;
const ll INF = 1e18;
const int MOD = 1e9+7;
int n, x, s, q, e, u, v, c, timer, R;
//segment
int t[N * 4];
//HLD
int tin[N], ind[N], depth[N], sz[N], heavy[N], chain[N], par[N];
//DP
int dp[N];
//tree
int sumw[N], numshop[N];
bool shop[N];
ii edge[N];
vector <ii> adj[N];
void update(int id,int l,int r,int pos,int val){
if (r < pos || l > pos) return;
if (l == r){
t[id] = val;
return;
}
int mid = (l + r) >> 1;
update(id*2,l,mid,pos,val);
update(id*2+1,mid+1,r,pos,val);
t[id] = min(t[id * 2],t[id * 2 + 1]);
}
int getMin(int id,int l,int r,int u,int v){
if (r < u || l > v) return INF;
if (u <= l && r <= v) return t[id];
int mid = (l + r) >> 1;
int t1 = getMin(id*2,l,mid,u,v);
int t2 = getMin(id*2+1,mid+1,r,u,v);
return min(t1,t2);
}
void getSize(int u,int p){
sz[u] = 1;
for (ii it : adj[u]){
if (it.fi == p) continue;
depth[it.fi] = depth[u] + 1;
par[it.fi] = u;
sumw[it.fi] = sumw[u] + it.se;
getSize(it.fi,u);
numshop[u] += numshop[it.fi];
sz[u] += sz[it.fi];
if (sz[heavy[u]] < sz[it.fi]){
heavy[u] = it.fi;
}
}
}
void getChain(int u,int p){
tin[u] = ++timer;
ind[timer] = u;
if (!heavy[u]) return;
chain[heavy[u]] = chain[u];
getChain(heavy[u],u);
for (ii it : adj[u]){
if (it.fi == p || it.fi == heavy[u]) continue;
chain[it.fi] = it.fi;
getChain(it.fi,u);
}
}
int LCA(int u,int v){
while (chain[u] != chain[v]){
if (depth[chain[u]] < depth[chain[v]]) swap(u,v);
u = par[chain[u]];
}
if (depth[u] > depth[v]) swap(u,v);
return u;
}
int getDepth(int u,int v){
return depth[u] + depth[v] - 2 * depth[LCA(u,v)];
}
int getDist(int u,int v){
int res = 0;
while (chain[u] != chain[v]){
if (depth[chain[u]] < depth[chain[v]]) swap(u,v);
res += sumw[u] - sumw[par[chain[u]]];
u = par[chain[u]];
}
if (depth[u] > depth[v]) swap(u,v);
res += sumw[v] - sumw[u];
return res;
}
void DP(int u,int p){
dp[u] = (shop[u] ? 0 : INF);
for (ii it : adj[u]){
if (it.fi == p) continue;
DP(it.fi,u);
dp[u] = min(dp[u],dp[it.fi] + it.se);
}
}
int getMinDist(int u,int v){
int res = INF;
while (chain[u] != chain[v]){
if (depth[chain[u]] < depth[chain[v]]) swap(u,v);
res = min(res,getMin(1,1,timer,tin[chain[u]],tin[u]));
u = par[chain[u]];
}
if (depth[u] > depth[v]) swap(u,v);
res = min(res,getMin(1,1,timer,tin[u],tin[v]));
return res;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
cin >> n >> s >> q >> e;
for (int i = 1; i < n; i++){
cin >> u >> v >> c;
adj[u].push_back({v,c});
adj[v].push_back({u,c});
edge[i] = {u,v};
}
for (int i = 1; i <= s; i++){
cin >> x;
shop[x] = 1;
numshop[x] = 1;
}
chain[e] = e;
getSize(e,0);
getChain(e,0);
DP(e,0);
for (int i = 1; i <= n; i++){
update(1,1,timer,tin[i],dp[i] - sumw[i]);
// cout << tin[i] << ' ';
}
// cout << '\n';
for (int i = 1; i < n; i++){
u = edge[i].fi;
v = edge[i].se;
if (depth[u] > depth[v]) swap(edge[i].fi,edge[i].se);
}
while (q--){
cin >> u >> R;
u = edge[u].se;
if (depth[R] != depth[u] + getDepth(u,R)) cout << "escaped" << '\n';
else{
if (numshop[u] == 0) cout << "oo" << '\n';
else{
cout << sumw[R] + getMinDist(R,u) << '\n';
}
}
}
return 0;
}
