#include <iostream>
#include <vector>
#include <map>
using namespace std;
int dfsSz(int i, int p, vector<vector<int> > & G, vector<int> & subTreeSz){
int res=1;
for (int j : G[i]){
if (j == p) continue;
res += dfsSz(j, i, G, subTreeSz);
}
return subTreeSz[i] = res;
}
void dfs(int i, int p, vector<vector<int> > & G, vector<vector<int> > & edgeId, vector<int> & subTreeSz, vector<vector<int> > & minstNode, vector<int> & minstSz, map<int,int> & minstNumNodes, int & diffMinst, vector<int> & res){
int heavyJ=-1, heavyId;
for (int ix=0; ix<(int)G[i].size(); ++ix){
int j=G[i][ix], jId = edgeId[i][ix];
if (j == p) continue;
if (heavyJ == -1 || subTreeSz[j] > subTreeSz[heavyJ]){
heavyJ = j;
heavyId = jId;
}
}
if (heavyJ == -1){
diffMinst = 0;
for (int m : minstNode[i]){
minstNumNodes[m] = 1;
diffMinst++;
}
return;
}
dfs(heavyJ, i, G, edgeId, subTreeSz, minstNode, minstSz, minstNumNodes, diffMinst, res);
res[heavyId] = diffMinst;
for (int ix=0; ix < (int)G[i].size(); ++ix){
int j = G[i][ix], jId = edgeId[i][ix];
if (j == heavyJ || j == p) continue;
int subDiffMinst=0;
map<int,int> subMinstNumNodes;
dfs(j, i, G, edgeId, subTreeSz, minstNode, minstSz, subMinstNumNodes, subDiffMinst, res);
res[jId] = subDiffMinst;
for (auto [m, cnt] : subMinstNumNodes){
if (cnt == -1) continue;
if (minstNumNodes[m] == 0){
minstNumNodes[m] = cnt;
++diffMinst;
} else if (minstNumNodes[m] + cnt == minstSz[m]){
minstNumNodes[m] = -1;
--diffMinst;
} else {
minstNumNodes[m] += cnt;
}
}
}
for (int m : minstNode[i]){
if (minstNumNodes[m] == 0){
minstNumNodes[m] = 1;
++diffMinst;
} else if (minstNumNodes[m] + 1 == minstSz[m]){
minstNumNodes[m] = -1;
--diffMinst;
} else {
minstNumNodes[m] += 1;
}
}
}
void solve(){
int N, M, K; cin >> N >> M >> K;
vector<vector<int> > G(N);
vector<vector<int> > edgeId(N);
for (int i=0; i<N-1; ++i){
int u, v; cin >> u >> v;
--u; --v;
G[u].push_back(v);
edgeId[u].push_back(i);
G[v].push_back(u);
edgeId[v].push_back(i);
}
vector<vector<int> > minstNode(N);
vector<int> minstSz(M);
for (int i=0; i<M; ++i){
int s; cin >> s;
minstSz[i] = s;
for (int j=0; j<s; ++j){
int u; cin >> u;
--u;
minstNode[u].push_back(i);
}
}
int root = 0;
vector<int> subTreeSz(N);
dfsSz(root, -1, G, subTreeSz);
vector<int> res(N-1);
map<int,int> minstNumNodes;
int diffMinst;
dfs(root, -1, G, edgeId, subTreeSz, minstNode, minstSz, minstNumNodes, diffMinst, res);
vector<int> ans;
for (int i=0; i<N-1; ++i){
if (res[i] >= K){
ans.push_back(i+1);
}
}
cout << ans.size() << '\n';
for (int n : ans) cout << n << ' ';
cout << '\n';
}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
solve();
return 0;
}
