// oooo
/*
be hengam shena mesle y dasto pa cholofti ~
bepa to masire dahane koose neyofti ~
;Amoo_Hasan;
*/
#include<bits/stdc++.h>
#pragma GCC optimize("O3,no-stack-protector,unroll-loops")
#pragma GCC target("avx2,fma")
using namespace std;
typedef long long ll;
typedef long long ld;
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define Sz(x) int((x).size())
#define all(x) (x).begin(), (x).end()
const ll inf = 1e18, N = 1e6 + 10, mod = 1e9 + 7, pr = 1000696969, Log = 30;
int h[N];
int st[N];
ll cnt[N];
int u[N], v[N];
int par[N][Log];
int t;
bool mark[N];
vector<ll> vc, ans, G[N];
bool cmp(int u, int v) {
return st[u] < st[v];
}
void dfs(int x, int p) {
mark[x] = 1, par[x][0] = p, st[x] = t++;
for(int i = 1; i < Log; i++)
par[x][i] = par[par[x][i - 1]][i - 1];
for(auto i : G[x]) {
if(mark[i]) continue;
h[i] = h[x] + 1;
dfs(i, x);
}
}
int get_par(int x, int y) {
for(int i = 0; i < Log; i++)
if((y >> i) & 1)
x = par[x][i];
return x;
}
int lca(int x, int y) {
if(h[x] > h[y]) swap(x, y);
y = get_par(y, h[y] - h[x]);
if(x == y) return x;
for(int i = Log - 1; i >= 0; i--) {
if(par[x][i] != par[y][i])
x = par[x][i], y = par[y][i];
}
return par[x][0];
}
void main_dfs(int x, int p) {
mark[x] = 1;
for(auto i : G[x]) {
if(mark[i]) continue;
main_dfs(i, x);
cnt[x] += cnt[i];
}
}
int main() {
fast_io;
int n, m, k;
cin >>n >>m >>k;
for(int i = 0; i < n - 1; i++) {
cin >>u[i] >>v[i];
G[u[i]].push_back(v[i]), G[v[i]].push_back(u[i]);
}
dfs(1, 0);
for(int i = 0; i < m; i++) {
int s; cin >>s;
vc.clear();
for(int j = 0; j < s; j++) {
int x; cin >>x;
vc.push_back(x);
}
sort(all(vc), cmp);
for(int i = 1; i < Sz(vc); i++) {
int lc = lca(vc[i], vc[i - 1]);
// cout<<"^&" <<vc[i - 1] <<" " <<vc[i] <<" " <<lc <<endl;
cnt[lc]--;
cnt[vc[i - 1]]++, cnt[vc[i]]++;
if(lc == vc[i]) cnt[vc[i]]--;
else if(lc == vc[i - 1]) cnt[vc[i - 1]]--;
}
int lc = lca(vc[0], vc.back());
cnt[lc]--;
cnt[vc[0]]++, cnt[vc.back()]++;
if(lc == vc[0]) cnt[vc[0]]--;
else if(lc == vc.back()) cnt[vc.back()]--;
}
memset(mark, 0, sizeof(mark));
main_dfs(1, 0);
for(int i = 1; i <= n; i++) {
cnt[i] /= 2;
}
for(int i = 0; i < n - 1; i++) {
if(h[u[i]] > h[v[i]]) swap(u[i], v[i]);
if(cnt[v[i]] >= k) ans.push_back(i + 1);
}
sort(all(ans));
cout<<Sz(ans) <<"\n";
for(auto i : ans) cout<<i <<" ";
return 0;
}
