#include <iostream>
#include <vector>
#include <set>
using namespace std;
const int N = 1<<17;
vector<pair<int,int>> nei[N];
vector<int> ers[N];
set<int> st[N];
int hei[N], par[N][20], Ans[N], Sz, n, m, k;
void dfs(int u, int p){
hei[u] = hei[p] + 1;
par[u][0] = p;
for (int i=1;i<17;i++)
par[u][i] = par[par[u][i-1]][i-1];
for (auto [i, ind] : nei[u]){
if (i == p)
continue;
dfs(i, u);
}
}
void moveUp(int &v, int d){
for (int i=0;i<17;i++)
if ((1<<i) & d)
v = par[v][i];
}
int LCA(int u, int v){
if (hei[u] > hei[v])
swap(u, v);
moveUp(v, hei[v] - hei[u]);
if (u == v)
return u;
for (int i=16;i>=0;i--){
if (par[u][i] != par[v][i])
u = par[u][i], v = par[v][i];
}
return par[u][0];
}
void dfs2(int u, int p, int id = 0){
for (auto [i, ind] : nei[u]){
if (i == p)
continue;
dfs2(i, u, ind);
if (st[i].size() > st[u].size())
swap(st[u], st[i]);
for (int j : st[i])
st[u].insert(j);
}
for (int i : ers[u])
st[u].erase(i);
if (st[u].size() >= k)
Sz++, Ans[id] = 1;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin>>n>>m>>k;
for (int i=1, a, b;i<n;i++){
cin>>a>>b;
nei[a].push_back({b, i});
nei[b].push_back({a, i});
}
dfs(1, 0);
for (int i=1, s, lca;i<=m;i++){
cin>>s>>lca;
st[lca].insert(i);
for (int k=1, v;k<s;k++)
cin>>v, lca = LCA(lca, v), st[v].insert(i);
ers[lca].push_back(i);
}
dfs2(1, 0);
cout<<Sz<<'\n';
for (int i=1;i<n;i++){
if (Ans[i])
cout<<i<<' ';
}
cout<<'\n';
}
