#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 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 = 2e5 + 5;
vi adj[mxn];
vi tree(mxn * 4);
int v[mxn];
vi dep(mxn);
vi par(mxn);
vi head(mxn);
vi pos(mxn);
vi sz(mxn);
vi heavy(mxn);
int timer = 0;
vi et;
vi unet(mxn);
int dfs(int node, int p){
int sts = 1;
par[node] = p;
int mx = 0;
int mxd = -1;
et.pb(node);
for(auto u : adj[node]){
if(u != p){
dep[u] = dep[node] + 1;
int s = dfs(u, node);
sts += s;
if(s > mx){
mx = s;
mxd = u;
}
}
}
heavy[node] = mxd;
sz[node] = sts;
return sts;
}
void construct(int node, int h){
head[node] = h;
pos[node] = timer++;
if(heavy[node] != -1)construct(heavy[node], h);
for(auto u : adj[node]){
if(u != par[node] && u != heavy[node]){
construct(u, u);
}
}
}
int n,m,k;
void update(int k, int x){
k += n;
tree[k] += x;
for(k/=2; k>=1; k/=2){
tree[k] = tree[k*2] + tree[k*2+1];
}
}
int quer(int l, int r){
//dout2(l,r);
l += n;
r += n;
int ret = 0;
while(l <= r){
if(l % 2 == 1)ret += tree[l++];
if(r % 2 == 0)ret += tree[r--];
l /= 2; r /= 2;
}
return ret;
}
void rangeupdate(int l, int r){
update(l, 1);
if(r != n-1){
update(r+1, -1);
}
}
void rangeunupdate(int l, int r){
update(l, -1);
if(r != n-1){
update(r+1, 1);
}
}
int pointquer(int x){
return quer(0, x);
}
void pathadd(int a, int b){
//out2(a,b);
a--; b--;
for(; head[a] != head[b]; b = par[head[b]]){
if(dep[head[a]] > dep[head[b]]){
swap(a,b);
}
rangeupdate(pos[head[b]], pos[b]);
//cout<<head[b]<<' '<<b<<'\n';
}
if(dep[a] > dep[b]){
swap(a,b);
}
rangeupdate(pos[a]+1, pos[b]);
//cout<<a<<' '<<b<<'\n';
//rangeunupdate(pos[a], pos[a]);
}
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
//ifstream cin(".in");
//ofstream cout(".out");
cin>>n>>m>>k;
vpii edges;
f0r(i,n-1){
in2(a,b);
a--;
b--;
adj[a].pb(b);
adj[b].pb(a);
edges.pb(mp(a,b));
}
dfs(0,-1);
f0r(i,n){
unet[et[i]] = i;
}
//vout(et);
construct(0,0);
//f0r(i,n)cout<<pos[i]<<' ';
//cout<<'\n';
mii ma;
f0r(i,n-1){
if(dep[edges[i].first] > dep[edges[i].second]){
ma[edges[i].first] = i+1;
}
else ma[edges[i].second] = i+1;
}
f0r(i,m){
in(s);
vi w(s);
f0r(j,s)cin>>w[j];
vpii x;
f0r(j,s){
x.pb(mp(unet[w[j]-1], w[j]));
}
sort(all(x));
x.pb(x[0]);
f0r(j,s){
pathadd(x[j].second, x[j+1].second);
}
}
vi ans;
FOR(i, 1, n){
//cout<<pointquer(pos[i])<<' ';
if(pointquer(pos[i]) >= 2*k){
ans.pb(ma[i]);
}
}
//out("");
sort(all(ans));
out(ans.size());
for(auto u : ans)cout<<u<<' ';
}
