#include <bits/stdc++.h>
using namespace std;
#define int long long
#define sp << " " <<
#define nl << "\n"
struct segtree{
int sz = 1;
vector<bool> a;
segtree(int n){
while(sz < n) sz *= 2;
a.assign(2*sz, false);
}
void update(int i, int x, int lx, int rx){
if(rx-lx==1) return void(a[x] = !a[x]);
int mx = (lx+rx)/2;
if(i<mx) update(i, 2*x+1, lx, mx);
else update(i, 2*x+2, mx, rx);
a[x] = max(a[2*x+1], a[2*x+2]);
}
void update(int i){ update(i, 0, 0, sz); }
bool get(int l, int r, int x, int lx, int rx){
if(r<=lx or rx<=l) return false;
if(l<=lx and rx<=r) return a[x];
int mx = (lx+rx)/2;
return get(l, r, 2*x+1, lx, mx) or get(l, r, 2*x+2, mx, rx);
}
bool get(int l, int r){ return get(l, r+1, 0, 0, sz); }
};
vector<vector<pair<int, int>>> g;
vector<array<int, 18>> p;
vector<int> t0, t1, dp, ans;
int dfsTimer = 0;
void dfs0(int u, int parent){
t0[u] = dfsTimer++;
p[u][0] = parent;
for(int i=1; i<18; ++i) p[u][i] = p[p[u][i-1]][i-1];
for(auto e : g[u]) if(e.first != parent) dfs0(e.first, u);
t1[u] = dfsTimer++;
}
bool isAncestor(int u, int v){
return t0[u]<=t0[v] and t1[v]<=t1[u];
}
int dfs1(int u){
for(auto edge : g[u]){
int v = edge.first, e = edge.second;
if(v==p[u][0]) continue;
ans[e] = dfs1(v);
dp[u] += ans[e];
}
return dp[u];
}
int lca(int u, int v){
if(isAncestor(u, v)) return u;
for(int i=17; i>=0; --i)
while(u and !isAncestor(p[u][i], v)) u = p[u][i];
return p[u][0];
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
int n, m, k, x, y; cin >> n >> m >> k;
g.resize(n), p.resize(n), t0.resize(n), t1.resize(n);
dp.assign(n, 0), ans.resize(n);
for(int i=1; i<n; ++i){
cin >> x >> y; --x, --y;
g[x].emplace_back(y, i);
g[y].emplace_back(x, i);
}
dfs0(0, 0);
segtree st(n+n);
while(m--){
int s; cin >> s;
vector<int> curr(s), updated;
for(int &i : curr) cin >> i, --i;
int x = curr[0];
for(int i : curr) x = lca(x, i);
for(int i : curr){
int u = i;
if(st.get(t0[u], t1[u])) continue;
for(int j=17; j>=0; --j)
while(u and isAncestor(x, p[u][j]) and !st.get(t0[p[u][j]], t1[p[u][j]]))
u = p[u][j];
st.update(t0[i]);
updated.push_back(t0[i]);
++dp[i];
if(u != x) u = p[u][0];
--dp[u];
}
for(int i : updated) st.update(i);
}
dfs1(0);
vector<int> res;
for(int i=1; i<n; ++i) if(ans[i]>=k) res.push_back(i);
// for(int i : ans) cout << i << ' ';
// cout nl;
cout << res.size() nl;
for(int i : res) cout << i << ' ';
}
