#include <vector>
#include <iostream>
#define int int64_t
using namespace std;
int log2(int n)
{
int res = 0;
for (; n; n >>= 1) res++;
return res;
}
struct graph
{
vector<vector<pair<int,int>>> adjlist;
vector<vector<int>> lcatable;
vector<int> lvl;
int n;
int logn;
vector<bool> shop;
void builddfs(int curr, int par, int l)
{
lvl[curr] = l;
lcatable[0][curr] = par;
for (auto p : adjlist[curr])
{
auto next = p.first;
if (next == par) continue;
builddfs(next, curr, l + 1);
}
}
void build()
{
logn = log2(n);
lcatable.resize(logn, vector<int>(n));
lvl.resize(n, - 1);
builddfs(0, -1, 0);
for (int l = 1; l < logn; l++)
{
for (int i = 0; i < n; i++)
{
lcatable[l][i] = (lcatable[l - 1][i] == -1) ? -1 : lcatable[l - 1][lcatable[l - 1][i]];
}
}
}
int lca(int a, int b)
{
if (lvl[a] < lvl[b]) swap(a, b);
int ldiff = lvl[a] - lvl[b];
int e = 1;
for (int i = 0; i < logn; i++)
{
if (ldiff & e) a = lcatable[i][a];
e *= 2;
}
if (a == b) return a;
for (int i = 0; i < logn; i++)
{
if (lcatable[i][a] != lcatable[i][b])
{
a = lcatable[i][a];
b = lcatable[i][b];
}
}
return lcatable[0][a];
}
int ddfs(int curr, int par, pair<int,int> fb)
{
// cerr << curr << " " << shop[curr] << "\n";
if (shop[curr] == true) return 0;
int mmin = 1e15;
for (auto p : adjlist[curr])
{
int next = p.first;
if (next == par) continue;
if (min(fb.first, fb.second) == min(curr, next) && max(fb.first, fb.second) == max(curr, next)) continue;
mmin = min(mmin, p.second + ddfs(next, curr, fb));
}
return mmin;
}
};
signed main()
{
int n, s, q, r;
cin >> n >> s >> q >> r;
graph g;
g.n = n;
g.adjlist.resize(n);
g.shop.resize(n, false);
vector<pair<int,int>> edges;
for (int i = 0; i < n - 1; i++)
{
int a, b, w;
cin >> a >> b >> w;
a--; b--;
edges.emplace_back(a, b);
g.adjlist[a].emplace_back(b, w);
g.adjlist[b].emplace_back(a, w);
}
for (int i = 0; i < s; i++)
{
int p;
cin >> p;
p--;
g.shop[p] = true;
}
g.build();
for (int i = 0; i < q; i++)
{
int r, v;
cin >> r >> v;
r--;
v--;
auto p = edges[r];
if (g.lvl[p.first] > g.lvl[p.second]) swap(p.first, p.second);
if (g.lca(p.second, v) != p.second)
{
cout << "escaped\n";
continue;
}
int d = g.ddfs(v, -1, p);
if (d >= 1e15)
{
cout << "oo\n";
}
else
{
cout << d << "\n";
}
}
}
