#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
// #pragma GCC optimize("Ofast,unroll-loops,fast-math")
// #pragma GCC target("popcnt")
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll,ll> pll;
#define sz size()
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define pb push_back
const int mod = ll(1e9)+7; //(b + (a%b)) % b (to mod -1%(10^9+7) correctly in c++ its -1 but its suppose to be 10^9+6
const ll MOD = 998244353; // (a%mod)*(binpow(b,mod-2,mod) = (a/b)%mod
const int N = ll(1e5)+100;
const long long inf = 2e18;
const long double eps = 1e-15L;
ll lcm(ll a, ll b) { return (a / __gcd(a,b))*b; }
ll binpow(ll a, ll b, ll m) { ll res=1; a %= m; while(b>0){ if(b&1)res=(res * a) % m; a=(a * a) % m; b/=2; } return res%m;}
void Freopen(string Key){ freopen((Key+".in").c_str(), "r", stdin); freopen((Key+".out").c_str(), "w", stdout); }
int n, s, q, e, depth[N], up[20][N], qu[N], qv[N], qw[N];
ll lift[20][N];
bool shop[N];
ll mn[N], dis[N];
vector<pair<int, int> > g[N];
void dfs(int v, int p = 0) {
if(!shop[v]) mn[v] = inf;
up[0][v] = p;
for(int j = 1; j <= 17; j ++) up[j][v] = up[j - 1][up[j - 1][v]];
for(auto to : g[v]) {
if(p == to.ff) continue;
depth[to.ff] = depth[v] + 1;
dis[to.ff] = dis[v] + to.ss;
dfs(to.ff, v);
if(mn[to.ff] != inf) mn[v] = min(mn[v], mn[to.ff] + to.ss);
}
}
void dfs1(int v, int p = 0) {
lift[0][v] = mn[v] - dis[v];
for(int j = 1; j <= 17; j ++) lift[j][v] = min(lift[j - 1][v], lift[j - 1][up[j - 1][v]]);
for(auto to : g[v]) {
if(p == to.ff) continue;
dfs1(to.ff, v);
}
}
int lca(int u, int v) {
if(depth[u] < depth[v]) swap(u, v);
// u is down further
int dif = depth[u] - depth[v];
for(int i = 17; i >= 0; i --) {
if(dif & (1<<i)) u = up[i][u];
}
// cout<<u<<" "<<v<<"\n";
if(u == v) return u;
for(int i = 17; i >= 0; i --) {
if(up[i][u] != up[i][v]) {
u = up[i][u];
v = up[i][v];
}
}
return up[0][v];
}
ll getmn(int v, int cnt) {
ll res = inf;
for(int j = 17; j >= 0; j --) {
if(cnt & (1 << j)) {
res = min(res, lift[j][v]);
v = up[j][v];
}
}
return res;
}
void Baizho() {
cin>>n>>s>>q>>e;
for(int i = 1; i <= n - 1; i ++) {
int u, v, w; cin>>u>>v>>w;
qu[i] = u;
qv[i] = v;
g[u].pb({v, w});
g[v].pb({u, w});
}
for(int i = 1; i <= s; i ++) {
int v; cin>>v;
shop[v] = 1;
}
dfs(e);
dfs1(e);
for(int i = 1; i <= n - 1; i ++) {
if(depth[qu[i]] > depth[qv[i]]) swap(qu[i], qv[i]);
}
while(q --) {
int id, r; cin>>id>>r;
// qu[id] has less depth than qv[id]
// cout<<lca(r, qv[id])<<" thelca \n";
if(lca(r, qv[id]) != qv[id]) cout<<"escaped\n";
else {
if(mn[qv[id]] == inf) cout<<"oo\n";
else {
cout<<getmn(r, depth[r] - depth[qv[id]] + 1) + dis[r]<<"\n";
}
}
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);cout.tie(0);
// precalc();
int ttt = 1;
// cin>>ttt;
for(int i=1; i<=ttt; i++) {Baizho(); }
}
