#include <bits/stdc++.h>
#define fr(i, a, b) for (int i = (a); i <= (b); ++i)
#define rf(i, a, b) for (int i = (a); i >= (b); --i)
#define fe(x, y) for (auto& x : y)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define all(x) (x).begin(), (x).end()
#define pw(x) (1LL << (x))
#define sz(x) (int)(x).size()
using namespace std;
mt19937_64 rng(228);
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define fbo find_by_order
#define ook order_of_key
template <typename T>
bool umn(T& a, T b) {
return a > b ? a = b, 1 : 0;
}
template <typename T>
bool umx(T& a, T b) {
return a < b ? a = b, 1 : 0;
}
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template <typename T>
using ve = vector<T>;
const int N = 1e5 + 5;
int n, s, q, root;
ve<pii> g[N];
int w[N];
int p[N], pe[N];
int tin[N], tout[N], timer;
int who[N];
ll dep[N];
bool mark[N];
ll dp[N];
void dfs(int v = root, int p = 0) {
::p[v] = p;
tin[v] = timer++;
if (mark[v]) {
dp[v] = 0;
} else {
dp[v] = 1e18;
}
fe (to, g[v]) {
if (to.fi == p) continue;
dep[to.fi] = w[to.se] + dep[v];
who[to.se] = to.fi;
pe[to.fi] = to.se;
dfs(to.fi, v);
umn(dp[v], dp[to.fi] + w[to.se]);
}
tout[v] = timer;
}
bool isUpper(int a, int b) {
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
int main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#else
ios::sync_with_stdio(0);
cin.tie(0);
#endif
cin >> n >> s >> q >> root;
fr (i, 1, n - 1) {
int a, b;
cin >> a >> b >> w[i];
g[a].pb({b, i});
g[b].pb({a, i});
}
fr (i, 1, s) {
int x;
cin >> x;
mark[x] = 1;
}
dfs();
fr (i, 1, q) {
int idx, v;
cin >> idx >> v;
int u = who[idx];
if (!isUpper(u, v)) {
cout << "escaped\n";
} else {
if (mark[v]) {
cout << "0\n";
continue;
}
int cur = v;
ll best = 1e18;
ll len = 0;
while (1) {
umn(best, len + dp[cur]);
if (cur == u) {
break;
}
len += w[pe[cur]];
cur = p[cur];
}
if (best == 1e18) {
cout << "oo\n";
} else {
cout << best << "\n";
}
}
}
return 0;
}
