#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
const ll INF = 1e18;
const int MAXN = 1e5 + 7;
const int MAXK = 20;
int jump[MAXK][MAXN];
ll mn[MAXK][MAXN];
int parent[MAXN];
vector<pii> g[MAXN];
pii range[MAXN];
ll dist[MAXN];
int up[MAXN];
int dep[MAXN];
int f[MAXN];
ll len[MAXN];
int n, s, q, source;
int t;
vector<pii> edges;
void dfs(int v, int p, int d, ll x){
dep[v] = d;
parent[v] = p;
len[v] = x;
range[v].fi = t++;
if(f[v]){
dist[v] = 0LL;
}else{
dist[v] = INF;
}
for(auto [u, c] : g[v]){
if(u == p){
continue;
}
up[u] = c;
dfs(u, v, d + 1, (ll)x + c);
dist[v] = min(dist[v], (ll)dist[u] + c);
}
range[v].se = t++;
}
void init(){
for(int i = 1; i <= n; i++){
jump[0][i] = parent[i];
mn[0][i] = (ll)dist[i] - len[i];
}
for(int j = 1; j < MAXK; j++){
for(int i = 1; i <= n; i++){
jump[j][i] = jump[j - 1][jump[j - 1][i]];
mn[j][i] = min(mn[j - 1][i], mn[j - 1][jump[j - 1][i]]);
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin >> n >> s >> q >> source;
for(int i = 1; i < n; i++){
int u, v, c;
cin >> u >> v >> c;
g[u].pb({v, c});
g[v].pb({u, c});
edges.pb({u, v});
}
for(int i = 1; i <= s; i++){
int v;
cin >> v;
f[v] = 1;
}
t = 0;
dfs(source, source, 0, 0LL);
init();
while(q--){
int ind, v;
cin >> ind >> v;
ind--;
int u = edges[ind].fi;
if(dep[edges[ind].se] > dep[u]){
u = edges[ind].se;
}
if(range[u].fi > range[v].fi || range[v].se > range[u].se){
cout << "escaped\n";
continue;
}
if(dist[u] == INF){
cout << "oo\n";
continue;
}
ll ans = dist[v];
int akt = v;
for(int j = MAXK - 1; j >= 0; j--){
if(dep[akt] - (1 << j) > dep[u]){
ans = min(ans, (ll)mn[j][akt] + len[v]);
akt = jump[j][akt];
}
}
ans = min(ans, (ll)dist[akt] - len[akt] + len[v]);
ans = min(ans, (ll)dist[u] - len[u] + len[v]);
cout << ans << '\n';
}
return 0;
}
