#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ii pair<int,int>
const int nax=2e5+5;
int n,m,k;
vector<pair<int,int>> adj[nax];
int timer=-1;
pair<int,int> tin[nax];
int tab[nax];
int dp[nax][20];
int depth[nax];
int ans[nax];
int pre[nax];
bool compare(int x,int y){
return tin[x].fi<tin[y].fi;
}
void euler(int x,int p){
tin[x].fi=++timer;
for (int i = 1; i < 20; ++i)
{
dp[x][i]=dp[dp[x][i-1]][i-1];
}
for(auto u:adj[x]){
if(u.fi==p) continue;
dp[u.fi][0]=x;
depth[u.fi]=depth[x]+1;
euler(u.fi,x);
}
tin[x].se=timer;
}
int jump(int x,int d){
for (int i = 19; i >= 0; --i)
{
if(d&(1<<i)) x=dp[x][i];
}
return x;
}
int lca(int x,int y){
if(depth[x]<depth[y]) swap(x,y);
x=jump(x,depth[x]-depth[y]);
if(x==y) return x;
for (int i = 19; i >= 0; --i)
{
if(dp[x][i]!=dp[y][i]){
x=dp[x][i];
y=dp[y][i];
}
}
return dp[x][0];
}
int res;
void dfs(int x,int p){
for(auto u:adj[x]){
if(u.fi==p) continue;
dfs(u.fi,x);
if(pre[u.fi]>=2*k){
ans[u.se]=1;
res++;
}
pre[x]+=pre[u.fi];
}
//cout <<x<<" "<<pre[x]<<endl;
}
int main(){
cin>>n>>m>>k;
for (int i = 0; i < n-1; ++i)
{
int x,y;
cin>>x>>y;
x--;y--;
adj[x].pb({y,i});
adj[y].pb({x,i});
}
euler(0,-1);
for (int i = 0; i < m; ++i)
{
int s;
cin>>s;
vector<int> state(s);
for (int j = 0; j < s; ++j)
{
cin>>state[j];
state[j]--;
}
sort(state.begin(),state.end(),compare);
for (int j = 0; j < s; ++j)
{
int l=lca(state[j],state[(j+1)%s]);
//cout <<state[j]<<" "<<state[(j+1)%s]<<" "<<l<<endl;
pre[l]-=2;
pre[state[j]]++;
pre[state[(j+1)%s]]++;
}
}
dfs(0,-1);
cout <<res<<endl;
for (int i = 0; i < n-1; ++i)
{
if(ans[i]) cout <<i+1<<" ";
}
}
