#include <iostream>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <algorithm>
#include <math.h>
#include <random>
#include <bitset>
#include <string>
#include <cstring>
#include <set>
#include <vector>
#include <map>
#include <stack>
using namespace std;
#define all(x) (x).begin(), (x).end()
#define max3(a, b, c) max(a, max(b, c))
#define min3(a, b, c) min(a, min(b, c))
#define mp make_pair
#define f first
#define se second
#define pb push_back
#define ppb pop_back
#define ll long long
#define ull unsigned long long
#define cntbit(x) __builtin_popcount(x)
#define endl '\n'
#define uset unordered_set
#define umap unordered_map
#define pii pair<int, int>
#define ld long double
#define pll pair<long long, long long>
struct edge {
int u, v, w;
};
const ll inf = 2e18;
const int N = 1e5 + 15;
int n, s, q, t, tin[N], tout[N], last;
ll dp[N], d[N];
vector <int> g[N];
vector <edge> e;
inline bool upper(int a, int b) {
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
void build(int v, int p = -1) {
tin[v] = ++last;
for(int i : g[v]) {
int to = (e[i].u == v ? e[i].v : e[i].u), w = e[i].w;
if(to != p) {
d[to] = d[v] + w;
build(to, v);
dp[v] = min(dp[v], dp[to] + w);
}
}
tout[v] = ++last;
}
int main() {
fill(dp, dp + N, inf);
scanf("%d%d%d%d", &n, &s, &q, &t);
for(int i = 1; i < n; ++i) {
int u, v, w;
scanf("%d%d%d", &u, &v, &w);
e.pb({u, v, w});
g[u].pb(e.size() - 1);
g[v].pb(e.size() - 1);
}
for(int i = 1; i <= s; ++i) {
int x;
scanf("%d", &x);
dp[x] = 0;
}
build(t);
for(int iter = 1; iter <= q; ++iter) {
int i, x;
scanf("%d%d", &i, &x);
int u = e[i - 1].u, v = e[i - 1].v;
if(tin[u] > tin[v])
swap(u, v);
if(!upper(u, x) || !upper(v, x)) {
puts("escaped");
continue;
}
ll val = min(dp[x], dp[v] + d[x] - d[v]);
if(val < inf)
printf("%lld\n", val);
else
puts("oo");
}
return 0;
}
