#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const int MaxN = 1e5 + 5;
const int MaxLog = 18;
struct Edge
{
int u, v;
};
int n, m, k;
Edge edges[MaxN];
vector<int> graph[MaxN];
void Inp()
{
cin >> n >> m >> k;
for (int x = 1; x < n; x++)
{
cin >> edges[x].u >> edges[x].v;
graph[edges[x].u].push_back(x);
graph[edges[x].v].push_back(x);
}
}
int curDFS;
int euler[MaxN];
int ending[MaxN];
int h[MaxN];
int par[MaxN];
void PreDFS(int u, int p)
{
curDFS++;
euler[u] = curDFS;
for (int x : graph[u])
{
int v = edges[x].u ^ edges[x].v ^ u;
if (v != p)
{
h[v] = h[u] + 1;
par[v] = u;
PreDFS(v, u);
}
}
ending[u] = curDFS;
}
int BinLift[MaxLog][MaxN];
void Build()
{
for (int x = 1; x <= n; x++)
{
BinLift[0][x] = par[x];
}
for (int x = 1; x < MaxLog; x++)
{
for (int y = 1; y <= n; y++)
{
BinLift[x][y] = BinLift[x - 1][BinLift[x - 1][y]];
}
}
}
int LCA(int u, int v)
{
if (h[u] != h[v])
{
if (h[u] > h[v])
{
swap(u, v);
}
int k = h[v] - h[u];
for (int x = MaxLog - 1; x >= 0; x--)
{
if (k & (1 << x))
{
v = BinLift[x][v];
}
}
}
if (u == v)
{
return v;
}
for (int x = MaxLog - 1; x >= 0; x--)
{
if (BinLift[x][u] != BinLift[x][v])
{
u = BinLift[x][u];
v = BinLift[x][v];
}
}
return par[u];
}
int sum[MaxN];
int query[2 * MaxN];
vector<int> res;
bool cmp(int a, int b)
{
return euler[a] < euler[b];
}
void DFS(int u, int p)
{
for (int x : graph[u])
{
int v = edges[x].u ^ edges[x].v ^ u;
if (v != p)
{
DFS(v, u);
if (sum[v] >= k)
{
res.push_back(x);
}
sum[u] += sum[v];
}
}
}
void Exc()
{
curDFS = 0;
PreDFS(1, -1);
Build();
for (int x = 1; x <= m; x++)
{
int p;
cin >> p;
vector<int> tmp;
for (int x = 1; x <= p; x++)
{
cin >> query[x];
tmp.push_back(query[x]);
}
sort(euler + 1, euler + p + 1, cmp);
for (int x = 2; x <= p; x++)
{
tmp.push_back(LCA(query[x - 1], query[x]));
}
sort(tmp.begin(), tmp.end(), cmp);
stack<int> st;
for (int x = 0; x < (int)tmp.size(); x++)
{
int y = x;
while (y < (int)tmp.size() && tmp[x] == tmp[y])
{
y++;
}
y--;
sum[tmp[x]]++;
while (!st.empty() && !(euler[st.top()] <= euler[tmp[x]] && euler[tmp[x]] <= ending[st.top()]))
{
st.pop();
}
if (st.empty())
{
sum[tmp[x]]--;
}
else
{
sum[st.top()]--;
}
st.push(tmp[x]);
x = y;
}
}
DFS(1, -1);
cout << (int)res.size() << "\n";
for (int x : res)
{
cout << x << " ";
}
}
int main()
{
//freopen("D.INP", "r", stdin);
//freopen("D.OUT", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int test = 1;
//cin >> test;
for (int x = 1; x <= test; x++)
{
Inp();
Exc();
}
return 0;
}
