#include <bits/stdc++.h>
#define int long long
using namespace std;
const int nmax = 1e5 + 5, nbit = 17, inf = 2e16;
using pii = pair<int,int>;
vector<pii> edg, g[nmax];
int inp, occ[nmax], h[nmax], depth[nmax], pin[nmax], pout[nmax], p[nmax][nbit], mval[nmax][nbit];
vector<int> preorder;
int dfs(int node, int f) {
preorder.push_back(node);
pin[node] = inp++;
p[node][0] = f;
int mn = inf;
depth[node] += depth[f], h[node] = h[f] + 1;
for(auto [x, w] : g[node])
if(x != f) depth[x] = w, mn = min(dfs(x, node), mn);
if(occ[node])
mn = depth[node];
if(mn == inf)
mval[node][0] = inf;
else
mval[node][0] = mn - depth[node];
pout[node] = inp - 1;
//cerr << node << ' ' << depth[node] << ' ' << mn << '\n';
return mn;
}
bool isanc(int f, int node) {
return pin[f] <= pin[node] && pout[node] <= pout[f];
}
signed main() {
int n, q, s, root;
cin >> n >> s >> q >> root;
for(int i = 1, a, b, w; i < n; i++) {
cin >> a >> b >> w;
g[a].push_back({b, w});
g[b].push_back({a, w});
edg.push_back({a, b});
}
for(int i = 0, x; i < s; i++) cin >> x, occ[x] = 1;
dfs(root, root);
for(auto &[a, b] : edg) if(isanc(b, a)) swap(a, b);
for(auto x : preorder) {
for(int i = 1; i < nbit; i++) {
p[x][i] = p[p[x][i - 1]][i - 1];
mval[x][i] = min(mval[x][i - 1], depth[x] - depth[p[x][i - 1]] + mval[p[x][i - 1]][i - 1]);
}
}
for(int tc = 0, node, jusqu; tc < q; tc++) {
cin >> jusqu >> node;
//cout << jusqu << ' ' << edg[jusqu - 1].first << ' ' << edg[jusqu - 1].second << '\n';
if(!isanc(edg[--jusqu].second, node))
cout << "escaped\n";
else {
jusqu = edg[jusqu].first;
//cout << node << ' ' << jusqu << '\n';
int mn = inf, total = 0, diff = h[node] - h[jusqu];
for(int i = nbit - 1; i >= 0; i--) {
if((1 << i) & diff) {
mn = min(total + mval[node][i], mn);
total += depth[node] - depth[p[node][i]];
node = p[node][i];
}
}
if(mn >= inf / 2)
cout << "oo\n";
else
cout << mn << '\n';
}
}
}
