#include <bits/stdc++.h>
#define pb push_back
#define int int64_t
#define pii pair<int, int>
#define X first
#define Y second
#define all(x) (x).begin(),(x).end()
#define lb lower_bound
#define ub upper_bound
using namespace std;
const int inf = 1e18;
void p(auto A){
for(auto e : A)cout << e << ' ';
cout << '\n';
}
void solve(){
int n, m, k; cin >> n >> m >> k;
vector<vector<pii>> g(n);
for(int i = 1; i< n; i++){
int c, d; cin >> c >> d; c--; d--;
g[c].pb({d, i});
g[d].pb({c, i});
}
int lg = 25;
vector<int>pre(n),pst(n);
vector<vector<int>> up(n, vector<int>(lg));
int t = 0;
auto dfs = [&](auto&& self, int u, int p)->void{
pre[u] = t++;
up[u][0] = p;
for(int i = 1; i< lg; i++)up[u][i] = up[up[u][i-1]][i-1];
for(auto [v, _] : g[u])if(v!=p){
self(self, v, u);
}
pst[u] = t++;
};
dfs(dfs, 0, 0);
auto anc = [&](int a, int b)->bool{
if(pre[a] <= pre[b] && pst[a] >= pst[b])return true;
return false;
};
auto lca = [&](int a, int b)->int{
if(anc(a, b))return a;
if(anc(b, a))return b;
for(int i = lg-1; i>= 0; i--)if(!anc(up[a][i], b))a=up[a][i];
return up[a][0];
};
vector<int> A(n);
for(int i = 0; i< m; i++){
int c; cin >> c;
vector<int> tmp;
for(int i = 0; i< c; i++){
int d; cin >> d; d--;
tmp.pb(d);
}
sort(all(tmp), [&](int a, int b){return pre[a] < pre[b];});
for(auto e : tmp)A[e]++;
for(int j = 1; j< c; j++)A[lca(tmp[j], tmp[j-1])]--;
A[lca(tmp.front(), tmp.back())]--;
}
vector<int> ans(n);
auto dfs2 = [&](auto&& self, int u, int p)->void{
for(auto [v, id] : g[u])if(v!=p){
self(self, v, u);
ans[id] = A[v];
A[u]+=A[v];
}
};
dfs2(dfs2, 0, 0);
int num = 0;
for(auto e : ans)if(e >= k)num++;
cout << num << '\n';
for(int i =1; i< n; i++)if(ans[i] >= k)cout << i << ' ';
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t = 1;
//cin >> t;
while(t--)solve();
}
