#include<bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define int long long
#define vi vector<int>
#define vvi vector<vector<int>>
#define pii pair<int, int>
#define vpii vector<pair<int, int>>
#define vc vector<char>
#define vb vector<bool>
#define mii map<int,int>
#define f0r(i,n) for(int i=0;i<n;i++)
#define FOR(i,k,n) for(int i=k;i<n;i++)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define in(a) int a; cin>>a
#define in2(a,b) int a,b; cin>>a>>b
#define in3(a,b,c) int a,b,c; cin>>a>>b>>c
#define in4(a,b,c,d) int a,b,c,d; cin>>a>>b>>c>>d
#define vin(v,n); vi v(n); f0r(i,n){cin>>v[i];}
#define out(a) cout<<a<<'\n'
#define out2(a,b) cout<<a<<' '<<b<<'\n'
#define out3(a,b,c) cout<<a<<' '<<b<<' '<<c<<'\n'
#define out4(a,b,c,d) cout<<a<<' '<<b<<' '<<c<<' '<<d<<'\n'
#define pout(a) cout<<a.first<<' '<<a.second<<'\n'
#define vout(v) for(auto u : v){cout<<u<<' ';} cout<<'\n'
#define dout(a) cout<<a<<' '<<#a<<'\n'
#define dout2(a,b) cout<<a<<' '<<#a<<' '<<b<<' '<<#b<<'\n'
#define yn(x); if(x){cout<<"YES"<<'\n';}else{cout<<"NO"<<'\n';}
const int leg = 1e9 + 7;
const int mod = 998244353;
using namespace std;
const int mxn = 1e5 + 5;
vi adj[mxn];
vi start(mxn);
vi par(mxn, -1);
vi et;
int n,m,k;
int timer = 0;
vi dep(mxn);
void dfs(int cur, int from){
par[cur] = from;
et.pb(cur);
start[cur] = timer;
if(from != -1)dep[cur] = dep[from] + 1;
timer++;
for(auto u : adj[cur]){
if(u != from){
dfs(u, cur);
}
timer++;
et.pb(cur);
}
}
vpii tree(mxn * 10, {4e18, 0});
void update(int k, int x, int d){
k += et.size();
tree[k] = mp(d, x);
for(k /=2; k >= 1; k/=2){
tree[k] = min(tree[k*2], tree[k*2+1]);
}
}
int quer(int l, int r){
l += et.size();
r += et.size();
pii ret = {4e18, 0};
while(l <= r){
if(l % 2 == 1)ret = min(ret, tree[l++]);
if(r % 2 == 0)ret = min(ret, tree[r--]);
l/=2; r/=2;
}
return ret.second;
}
int lca(int a, int b){
if(start[a] > start[b])swap(a,b);
return quer(start[a], start[b]);
}
vi path(int a, int b){
if(a == b)return {a};
vi c;
vi d;
c.pb(a);
int l = lca(a,b);
while(a != l){
a = par[a];
c.pb(a);
}
d.pb(b);
while(b != l){
b = par[b];
d.pb(b);
}
if(d.size() != 0)d.pop_back();
reverse(all(d));
for(auto u : d)c.pb(u);
return c;
}
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
//ifstream cin(".in");
//ofstream cout(".out");
cin>>n>>m>>k;
map<pii, int>edge;
vi deg(n);
f0r(i,n-1){
in2(a,b);
a--;
b--;
deg[a]++;
deg[b]++;
adj[a].pb(b);
adj[b].pb(a);
edge[mp(a,b)] = i;
edge[mp(b,a)] = i;
}
//n<=10000 && m <= 2000
if(n<=10000 && m <= 2000){
dfs(0, -1);
f0r(i, et.size()){
update(i, et[i], dep[et[i]]);
}
//vout(et);
//f0r(i,n)cout<<par[i]<<' ';
//cout<<'\n';
f0r(i, n){
//cout<<start[i]<<' ';
}
//cout<<'\n';
//vout(path(4,2));
//out(lca(0,2));
//vout(path(0, 2));
//vout(path(4,4));
vi tot(n-1);
f0r(i,m){
in(s);
vi v(s);
f0r(j, s)cin>>v[j];
f0r(j,s)v[j]--;
vi cnt(n-1);
//vout(v);
//dout(lca(1,4));
//vout(path(1,4));
f0r(j, s-1){
vi cur = path(v[j], v[j+1]);
f0r(K, cur.size() - 1){
cnt[edge[mp(cur[K], cur[K+1])]] = 1;
}
}
f0r(j, n-1)tot[j] += cnt[j];
}
vi ans;
f0r(i, n-1){
if(tot[i] >= k)ans.pb(i + 1);
}
sort(all(ans));
out(ans.size());
vout(ans);
}
else{
//vout(deg);
int ep = 0;
f0r(i,n){
if(deg[i] == 1)ep = i;
}
vb vis(n);
vi path;
path.pb(ep);
vis[ep] = 1;
int cur = ep;
//cout<<cur<<endl;
vi edgedex;
while(true){
for(auto u : adj[cur]){
if(vis[u])continue;
edgedex.pb(edge[mp(u, cur)]);
vis[u] = 1;
cur = u;
path.pb(cur);
}
if(deg[cur] == 1)break;
//cout<<cur<<endl;
}
//vout(edgedex);
//vout(path);
vi pathdex(n);
f0r(i,n){
pathdex[path[i]] = i;
}
vi cnt(n-1);
vi dif(n-1);
f0r(tt, m){
in(s);
vin(v,s);
//vout(v);
f0r(i,s)v[i]--;
//vout(v);
int mn = 4e18;
int mx = -1;
f0r(i,s){
mn = min(mn, pathdex[v[i]]);
mx = max(mx, pathdex[v[i]]);
}
mx--;
//out2(mn, mx);
dif[mn]++;
if(mx != n-1)dif[mx+1]--;
}
cnt[0] = dif[0];
FOR(i, 1, n-1){
cnt[i] = dif[i] + cnt[i-1];
}
//vout(cnt);
vi ans;
f0r(i, n-1){
if(cnt[i] >= k){
ans.pb(edgedex[i]+1);
}
}
out(ans.size());
vout(ans);
}
}
