#include<bits/stdc++.h>
#define taskname "B"
using namespace std;
const int lim = 1e5 + 5;
const int LG = 17;
int n, m, k, tdfs = 0, a[lim], b[lim], v2e[lim], low[lim], tail[lim], h[lim], f[lim], up[LG][lim];
vector<int>g[lim];
void dfs(int s){
low[s] = ++tdfs;
for(int& i : g[s]){
int d = a[i] ^ b[i] ^ s;
if(d != up[0][s]){
h[d] = h[up[0][d] = s] + 1;
v2e[d] = i;
dfs(d);
}
}
tail[s] = tdfs;
}
int lca(int u, int v){
if(h[u] < h[v]){
swap(u, v);
}
for(int x = h[u] - h[v], i = 0; i < LG; i++){
if(x >> i & 1){
u = up[i][u];
}
}
if(u == v){
return u;
}
for(int i = LG - 1; i > -1; i--){
if(up[i][u] != up[i][v]){
u = up[i][u];
v = up[i][v];
}
}
return up[0][u];
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if(fopen(taskname".inp", "r")){
freopen(taskname".inp", "r", stdin);
}
cin >> n >> m >> k;
for(int i = 1; i < n; i++){
cin >> a[i] >> b[i];
g[a[i]].push_back(i);
g[b[i]].push_back(i);
}
memset(f, up[0][0] = up[0][1] = h[1] = 0, sizeof(f));
dfs(1);
for(int i = 1; i < LG; i++){
for(int j = 0; j <= n; j++){
up[i][j] = up[i - 1][up[i - 1][j]];
}
}
for(int _ = 0; _ < m; _++){
int siz;
cin >> siz;
vector<int>ver(siz);
for(int& x : ver){
cin >> x;
}
sort(ver.begin(), ver.end(), [&] (int i, int j){
return low[i] < low[j];
});
for(int i = siz - 2; i > -1; i--){
ver.push_back(lca(ver[i], ver[i + 1]));
}
sort(ver.begin(), ver.end(), [&] (int i, int j){
return low[i] < low[j];
});
ver.resize(unique(ver.begin(), ver.end()) - ver.begin());
vector<int>stk(1, ver[0]);
for(int i = 1; i < ver.size(); stk.push_back(ver[i++])){
while(tail[stk.back()] < low[ver[i]]){
stk.pop_back();
}
f[ver[i]]++;
f[stk.back()]--;
}
}
vector<int>p(n - 1);
iota(p.begin(), p.end(), 2);
sort(p.begin(), p.end(), [&] (int i, int j){
return h[i] > h[j];
});
for(int& x : p){
for(int& i : g[x]){
int y = a[i] ^ b[i] ^ x;
if(h[y] > h[x]){
f[x] += f[y];
}
}
}
vector<int>ans;
for(int i = 2; i <= n; i++){
if(f[i] >= k){
ans.push_back(v2e[i]);
}
}
sort(ans.begin(), ans.end());
cout << ans.size() << "\n";
for(int& x : ans){
cout << x << " ";
}
}
