#include <iostream>
#include <vector>
#include <string>
#include <functional>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <set>
#include <queue>
#include <numeric>
#include <cmath>
#include <cstring>
#include <climits>
#include <stack>
#include <math.h>
#include <iomanip>
#include <bitset>
typedef long long ll;
using namespace std;
using vi = vector<int>;
using pi = pair<int, int>;
using vpi = vector<pi>;
#define fst first
#define snd second
#define pb push_back
#define rsz resize
#define all(x) (x).begin(), (x).end()
#define sz(x) int(x.size())
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
template<class T> bool ckmax(T& a, const T& b) {
return a < b ? a = b, 1 : 0;
}
template<class T> bool ckmin(T& a, const T& b) {
return a > b ? a = b, 1 : 0;
}
const int MAXN = 1e5;
const ll INF = 1e18;
vector<pair<int, ll>> adj[MAXN];
int st[MAXN], en[MAXN];
ll ht[MAXN]; int par[MAXN];
ll dp[MAXN];
bool shop[MAXN];
int timer = 0;
int e;
void tour(int x, int p) {
st[x] = timer++;
dp[x] = INF;
for (auto cv : adj[x]) {
int v = cv.fst; ll w = cv.snd;
if (v!=p) {
ht[v] = ht[x] + w;
par[v] = x;
tour(v, x);
ckmin(dp[x], dp[v] + w);
}
}
if (shop[x]) dp[x] = 0;
en[x] = timer;
}
bool is_descendant(int b, int a) {
return (st[a]<=st[b] && en[a]>=en[b]);
}
pair<int , ll> pow2j[MAXN][18];
void fill(int log2d, int n) {
par[e] = -1;
F0R(i, n) pow2j[i][0] = {par[i], (i==e? dp[i] : min(dp[i], dp[par[i]]))};
for (int p = 1; p< log2d; p++) {
F0R(i, n) {
int hway = pow2j[i][p-1].fst;
if (hway==-1) pow2j[i][p] = {-1, pow2j[i][p-1].snd};
else pow2j[i][p] = {pow2j[hway][p-1].fst, min(pow2j[i][p-1].snd, pow2j[hway][p-1].snd)};
}
}
}
int main() {
int n, s, q; cin >> n >> s >> q >> e;
e--;
vector<pi> roads;
F0R(i, n-1) {
int a, b; ll w; cin >> a >> b >> w;
a--, b--;
roads.pb({a,b});
adj[a].pb({b, w}); adj[b].pb({a, w});
}
F0R(i, s) {
int x; cin >> x; x--;
shop[x] = true;
}
tour(e, e);
int log2d = (int)(log2(n)) + 1;
fill(log2d, n);
F0R(i, n) dp[i]-=ht[i];
// F0R(i, n) cout << ht[i] << endl;
// cout << "dp: " << endl;
// F0R(i, n) cout << dp[i] << endl;
// // F0R(p, log2d) {
// // F0R(i, n) {
// // cout << pow2j[i][p].fst << " ";
// // }
// // cout << endl;
// // }
// return 0;
//cout << dp[7] << endl; return 0;
F0R(j, q) {
int i, r; cin >> i >> r; r--, i--;
int top;
if (is_descendant(roads[i].fst, roads[i].snd)) {
top = roads[i].fst;
} else top = roads[i].snd;
//cout << "top: " << top << endl;
if (!is_descendant(r, top)) cout << "escaped" << '\n';
else {
if (r==top) {
ll ans = dp[top] + ht[r];
if (ans>1e14) cout << "oo" << '\n';
else cout << ans << '\n';
continue;
}
int at = r;
ll curmin = dp[r];
for (int p = log2d - 1; p>=0; p--) {
if (pow2j[at][p].fst!=-1 && !is_descendant(top, pow2j[at][p].fst)) {
ckmin(curmin, pow2j[at][p].snd);
at = pow2j[at][p].fst;
//cout << "from: " << r << " to " << at << endl;
}
}
ckmin(curmin, dp[par[at]]);
//cout << "fin: " << curmin << " " << ht[r] << endl;
curmin+= ht[r];
if (curmin>1e14) cout << "oo" << '\n';
else cout << curmin << '\n';
}
}
}
