#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define pb push_back
#define ii pair<int, int>
#define sz(v) (int)v.size()
#define all(v) v.begin(), v.end()
using namespace std;
const int N=1e5+5, mod = 1e9+7, inf = 1e18, L = 18;
int n, s, q, e, timer=0;
vector<ii> adj[N];
vector<ii> edges;
int in[N], out[N], d[N], r[N];
int up[N][L], len[N][L], mn[N][L];
bool shop[N];
vector<int> seg;
void update(int node, int l, int r, int idx, int val) {
if(l>idx || r<idx) return;
if(l==r) {
seg[node] += val;
return;
}
int mid = (l+r)>>1;
update(node<<1, l, mid, idx, val); update(node<<1|1, mid+1, r, idx, val);
seg[node] = seg[node<<1]+seg[node<<1|1];
}
int get(int node, int l, int r, int ql, int qr) {
if(l>qr || r<ql) return 0;
if(ql<=l && r<=qr) return seg[node];
int mid = (l+r)>>1;
return get(node<<1, l, mid, ql, qr) + get(node<<1|1, mid+1, r, ql, qr);
}
void dfs(int u, int p, int w_) {
in[u] = ++timer;
d[u] = d[p]+1;
// cout << u << ":" << len[u][1] << " " << up[u][0] << " " << len[up[u][0]][0]<< '\n';
up[u][0] = p;
for (int i=1; i<L; i++) up[u][i] = up[up[u][i-1]][i-1];
len[u][0] = w_;
for (int i=1; i<L; i++) len[u][i] = len[u][i-1] + len[up[u][i-1]][i-1];
int res = inf;
for (ii it: adj[u]) {
int v = it.fi, w = it.se;
if(v!=p) {
dfs(v, u, w);
res = min(res, w+r[v]);
}
}
if(shop[u]) res = 0;
r[u] = res;
out[u] = timer;
}
void dfs_mn(int u, int p) {
mn[u][0] = min(r[u], len[u][0]+r[p]);
for (int i=1; i<L; i++) mn[u][i] = min(mn[u][i-1], mn[up[u][i-1]][i-1]+len[u][i-1]);
for (ii it: adj[u]) {
int v = it.fi, w = it.se;
if(v!=p) {
dfs_mn(v, u);
}
}
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> s >> q >> e;
edges.pb({0, 0});
for (int i=1; i<n; i++) {
int u, v, w; cin >> u >> v >> w;
adj[u].pb({v, w});
adj[v].pb({u, w});
edges.pb({u, v});
}
for (int i=0; i<s; i++) {
int c; cin >> c;
shop[c] = 1;
}
d[0] = -1;
dfs(e, 0, 0);
r[0] = inf;
dfs_mn(e, 0);
seg.assign(4*n+5, 0);
while(q--) {
int road, vill; cin >> road >> vill;
int u = edges[road].fi, v = edges[road].se;
if(up[u][0]==v) swap(u, v);
update(1, 1, n, in[v], 1);
if(out[v]+1<=n) update(1, 1, n, out[v]+1, -1);
int res = get(1, 1, n, 1, in[vill]);
update(1, 1, n, in[v], -1);
if(out[v]+1<=n) update(1, 1, n, out[v]+1, 1);
if(res==0) {
cout << "escaped\n";
continue;
}
int k = d[vill]-d[v];
int ans = r[vill], dist = 0;
for (int i=0; i<L; i++) {
if ((1<<i)&k) {
ans = min(ans, mn[vill][i]+dist);
dist += (1<<i);
vill = up[vill][i];
}
}
if(ans>=inf) cout << "oo\n";
else cout << ans << '\n';
}
// cout << "##########\n";
// cout << mn[1][0];
}
