// Born_To_Laugh - Hughie Do
#include <bits/stdc++.h>
#define alle(AC) AC.begin(), AC.end()
#define fi first
#define se second
using namespace std;
typedef long long ll;
[[maybe_unused]] const ll MOD = 998244353, INF = 1e9 + 7;
const int maxn = 1e5 + 10;
int n, m, k;
vector<pair<int,int>> adj[maxn];
vector<int> ans;
int eid[maxn], tin[maxn], val[maxn];
int dep[maxn];
int binlift[maxn][20];
int id = 0;
void dfs(int a, int par){
tin[a] = ++id;
for(auto &edge: adj[a]){
int elm = edge.fi;
if(elm == par)continue;
binlift[elm][0] = a;
for(int i=1; i<20; ++i){
binlift[elm][i] = binlift[binlift[elm][i - 1]][i - 1];
}
eid[elm] = edge.se;
dep[elm] = dep[a] + 1;
dfs(elm, a);
}
}
void dfscal(int a, int par){
for(auto &edge: adj[a]){
int elm = edge.fi;
if(elm == par)continue;
dfscal(elm, a);
val[a] += val[elm];
}
if(val[a] >= 2 * k && a != 1)ans.push_back(eid[a]);
}
int lca(int a, int b){
if(dep[a] < dep[b])swap(a, b);
int k = dep[a] - dep[b];
for(int i=0; i<20; ++i){
if(k & (1 << i))a = binlift[a][i];
}
if(a == b)return a;
for(int i=19; i>=0; --i){
if(binlift[a][i] != binlift[b][i]){
a = binlift[a][i];
b = binlift[b][i];
}
}
return binlift[a][0];
}
void solve(){
cin >> n >> m >> k;
for(int i=1; i<n; ++i){
int a, b;cin >> a >> b;
adj[a].push_back({b, i});
adj[b].push_back({a, i});
}
dfs(1, -1);
for(int i=1; i<=m; ++i){
int x;cin >> x;
vector<int> sth(x + 1, 0);
for(int j=1; j<=x; ++j)cin >> sth[j];
sort(sth.begin() + 1, sth.end(), [&](int a, int b){
return tin[a] < tin[b];
});
for(int j=1; j<=x; ++j){
int b, a = sth[j];
if(j == x)b = sth[1];
else b = sth[j + 1];
int c = lca(a, b);
val[a]++;
val[b]++;
val[c] -= 2;
}
}
dfscal(1, -1);
sort(alle(ans));
cout << ans.size() << '\n';
for(auto &elm: ans)cout << elm << ' ';
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
solve();
}
