#include <bits/stdc++.h>
using namespace std;
using graph = vector<vector<pair<int, int>>>;
int main() {
int n, m;
cin >> n >> m;
graph G(n);
for (int i = 0; i < m; ++i) {
int u, v;
cin >> u >> v;
--u; --v;
G[u].emplace_back(v, i);
G[v].emplace_back(u, i);
}
vector<int> used(m);
vector<int> order;
function<void (int)> dfs = [&](int u) {
while (!G[u].empty()) {
auto [v, i] = G[u].back();
G[u].pop_back();
if (!used[i]) {
used[i] = true;
dfs(v);
}
}
order.push_back(u);
};
dfs(0);
vector<bool> marc(n);
vector<vector<int>> cycles;
stack<int> st;
for (int x: order) {
if (marc[x]) {
cycles.emplace_back(1, x);
while (st.top() != x) {
marc[st.top()] = false;
cycles.back().push_back(st.top());
st.pop();
}
st.pop();
}
marc[x] = true;
st.push(x);
}
for (vector<int> &xs: cycles) {
cout << xs.size() << " ";
for (int x: xs)
cout << x + 1 << " ";
cout << "\n";
}
}
