///TRAN THAI BAO :3
#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
typedef pair<int, int> pii;
#define maxN 100007
int n, m, k;
vector<int>adj[maxN];
pii eList[maxN];
int stt[maxN];
int in[maxN];
int ou[maxN];
int up[maxN][20];
int h[maxN] = {0};
int curT = 0;
int f[maxN] = {0};
void dfs(int u, int p)
{
h[u] = h[p]+1;
in[u] = ++curT;
up[u][0] = p;
int v;
for(int i = 0; i < adj[u].size(); i++)
{
v = adj[u][i];
if(v == p)
continue;
dfs(v, u);
}
ou[u] = curT;
}
bool cmp(int x, int y)
{
return in[x] < in[y];
}
int lca(int u, int v)
{
if(h[u] < h[v]) swap(u, v);
int d = h[u] - h[v];
for(int i = 0; i < 20; i++)
if((d>>i)&1)
u = up[u][i];
if(u == v)
return u;
for(int i = 19; i >= 0; i--)
if(up[u][i] != up[v][i])
{
u = up[u][i];
v = up[v][i];
}
return up[u][0];
}
void dfsAns(int u, int p)
{
int v;
for(int i = 0; i < adj[u].size(); i++)
{
v = adj[u][i];
if(v == p)
continue;
dfsAns(v, u);
f[u] += f[v];
}
}
void solve()
{
cin >> n >> m >> k;
int u, v;
for(int i = 1; i < n; i++)
{
cin >> u >> v;
eList[i] = {u, v};
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1, 1);
for(int i = 1; i < n; i++)
{
if(up[eList[i].first][0] != eList[i].second)
swap(eList[i].first, eList[i].second);
stt[eList[i].first] = i;
}
for(int i = 1; i < 20; i++)
for(int j = 1; j <= n; j++)
up[j][i] = up[up[j][i-1]][i-1];
for(int i = 0; i < m; i++)
{
int s, tmp;
cin >> s;
vector<int>a;
for(int j = 0; j < s; j++)
{
cin >> tmp;
a.push_back(tmp);
}
sort(a.begin(), a.end(), cmp);
a.push_back(a.front());
for(int j = 0; j < a.size()-1; j++)
{
f[a[j]]++;
f[lca(a[j], a[j+1])]--;
}
}
dfsAns(1, 1);
int cnt = 0;
vector<int>ans;
for(int i = 1; i <= n; i++)
if(f[i] >= k)
{
cnt++;
ans.push_back(stt[i]);
}
sort(ans.begin(), ans.end());
cout << cnt << "\n";
for(int i = 0; i < cnt; i++)
cout << ans[i] << " ";
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
solve();
return 0;
}
