#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;
const int N=1e5+10,LG=18;
vector<pair<int,int>> ma[N];
int par[N][LG],h[N],sm[N],tmp=0,tin[N],tout[N],edg[N];
void dfs(int x,int p=0)
{
h[x]=h[p]+1;
par[x][0]=p;
for(int j=1;j<LG;j++)par[x][j]=par[par[x][j-1]][j-1];
tin[x]=tmp++;
for(auto [y,id]:ma[x])
{
if(y^p)
edg[y]=id,dfs(y,x);
}
tout[x]=tmp;
}
int lca(int x,int y)
{
if(h[x]>h[y])swap(x,y);
for(int j=LG-1;j>=0;j--)
{
if(h[par[y][j]]>=h[x])
{
y=par[y][j];
}
}
if(x==y)return x;
for(int j=LG-1;j>=0;j--)
{
if(par[x][j]!=par[y][j])
{
x=par[x][j];
y=par[y][j];
}
}
return par[x][0];
}
bool bytin(int x,int y){
return tin[x]<tin[y];
}
void dfs(int x,vector<int>&pos)
{
while(pos.size()>0 and tout[pos.back()]<=tout[x])
{
int y=pos.back();
pos.pop_back();
sm[y]++;
sm[x]--;
//<<"Add to path "<<x<<' '<<y<<endl;
dfs(y,pos);
}
}
void dfs_(int x,int p=0)
{
//<<"At "<<x<<' '<<sm[x]<<endl;
for(auto [y,id]:ma[x])
{
if(y^p)
dfs_(y,x),sm[x]+=sm[y];
}
//<<"fnl "<<x<<' '<<sm[x]<<endl;
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,m,k;
cin>>n>>m>>k;
for(int i=1;i<n;i++)
{
int x,y;
cin>>x>>y;
ma[x].push_back({y,i});
ma[y].push_back({x,i});
}
dfs(1);
for(int i=0;i<m;i++)
{
int sz;
cin>>sz;
vector<int> cur;
for(int j=0;j<sz;j++)
{
int x;
cin>>x;
cur.push_back(x);
}
sort(begin(cur),end(cur),bytin);
set<int> nodes(begin(cur),end(cur));
for(int j=0;j<sz;j++)
{
int x=lca(cur[j],cur[(j+1)%sz]);
nodes.insert(x);
}
cur.clear();
for(auto x:nodes)cur.push_back(x);
sort(begin(cur),end(cur),bytin);
reverse(begin(cur),end(cur));
int rt=cur.back();
cur.pop_back();
dfs(rt,cur);
}
dfs_(1);
vector<int> ans;
for(int i=2;i<=n;i++)
{
if(sm[i]>=k)ans.push_back(edg[i]);
}
sort(begin(ans),end(ans));
cout<<ans.size()<<endl;
for(auto x:ans)cout<<x<<' ';
cout<<endl;
}
