#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
#ifdef _DEBUG
#define dout(x) clog << "Line " << __LINE__ << ": " << #x << "=" << (x) << el
#else
#define dout(x)
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define uid(a,b) uniform_int_distribution<int>(a,b)(rng)
#define ins insert
#define ssize(x) (int((x).size()))
#define bs(args...) binary_search(args)
#define lb(args...) lower_bound(args)
#define ub(args...) upper_bound(args)
#define all(x) (x).begin(),(x).end()
#define mp(a, b) make_pair(a, b)
#define mt(args...) make_tuple(args)
#define pb(x) push_back(x)
#define eb(args...) emplace_back(args)
#define ff first
#define ss second
#define die exit(0)
template<typename T>
using vc = vector<T>;
template<typename T>
using uset = unordered_set<T>;
template<typename A, typename B>
using umap = unordered_map<A, B>;
template<typename T, typename Comp>
using pq = std::priority_queue<T, vc<T>, Comp>;
template<typename T>
using maxpq = pq<T, less<T>>;
template<typename T>
using minpq = pq<T, greater<T>>;
template<typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
using db = double;
using ld = long double;
using ll = long long;
using ull = unsigned long long;
using pi = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vc<int>;
using vll = vc<ll>;
using vpi = vc<pi>;
using vpll = vc<pll>;
using str = string;
constexpr char el = '\n';
constexpr char sp = ' ';
constexpr int inf = 0x3f3f3f3f;
constexpr ll llinf = 0x3f3f3f3f3f3f3f3fLL;
// ---------------------------------------------------------------------
const int LG = 20;
const int N = 1e5+5;
int n, s, q, e, up[LG][N], dep[N];
ll mag[LG][N], dis[N];
tuple<int, int, int> eg[N];
bool is_shop[N];
vpi adj[N];
int anc(int x, int k){
for(int i = 0; k > 0; ++i){
if(k&1)
x = up[i][x];
k /= 2;
}
return x;
}
int lca(int a, int b){
a = anc(a, max(0, dep[a]-dep[b]));
b = anc(b, max(0, dep[b]-dep[a]));
if(a==b)
return a;
for(int i = LG-1; i >= 0; --i)
if(up[i][a]!=up[i][b]){
a = up[i][a];
b = up[i][b];
}
return up[0][a];
}
void dfs(int v, int p){
up[0][v] = p;
if(is_shop[v])
mag[0][v] = dis[v];
else
mag[0][v] = llinf;
for(auto[u, w]: adj[v]){
if(u==p)
continue;
dep[u] = dep[v] + 1;
dis[u] = dis[v] + w;
dfs(u, v);
mag[0][v] = min(mag[0][v], mag[0][u]);
}
}
signed main() {
ios::sync_with_stdio(0); cin.tie(0);
cout << fixed; clog << fixed; clog << unitbuf;
#ifdef _DEBUG
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
freopen("debug.txt", "w", stderr);
#else
//freopen(".in", "r", stdin);
//freopen(".out", "w", stdout);
#endif
cin >> n >> s >> q >> e;
for(int i = 1; i < n; ++i){
int a, b, w;
cin >> a >> b >> w;
adj[a].eb(b, w);
adj[b].eb(a, w);
eg[i] = {a, b, w};
}
while(s--){
int x;
cin >> x;
is_shop[x] = 1;
}
dfs(e, 0);
for(int i = 1; i <= n; ++i)
if(mag[0][i]<llinf)
mag[0][i] -= 2*dis[i];
#ifdef _DEBUG
clog << "Line " << __LINE__ << ":\n";
for(int i = 1; i <= n; ++i)
clog << dep[i] << sp << dis[i] << el;
clog << el;
#endif
for(int i = 1; i < LG; ++i)
for(int j = 1; j <= n; ++j){
up[i][j] = up[i-1][up[i-1][j]];
mag[i][j] = min(mag[i-1][j], mag[i-1][up[i-1][j]]);
}
while(q--){
int i, r;
cin >> i >> r;
auto[v, u, _] = eg[i];
if(lca(v, r)!=v || lca(u, r) != u){
cout << "escaped\n";
continue;
}
if(dep[v]<dep[u])
swap(v, u);
u = r;
ll mi = llinf;
for(int i = LG-1; i >= 0; --i)
if(dep[up[i][r]] >= dep[v]){
mi = min(mi, mag[i][r]);
r = up[i][r];
}
mi = min(mi, mag[0][r]);
if(mi >= llinf)
cout << "oo\n";
else
cout << dis[u] + mi << el;
}
}
