#include <bits/stdc++.h>
 
using namespace std;
 
ifstream f("biconex.in");
ofstream g("biconex.out");
 
stack <pair <int, int>> st;
 
vector <unordered_set <int>> bcc;
vector <int> gr[100001];
 
int tin[100001], low[100001];
int N, M;
 
void Read(){
	f >> N >> M;
	while(M--){
		int x, y;
		f >> x >> y;
		gr[x].emplace_back(y);
		gr[y].emplace_back(x);
	}
}
 
void find_bcc(int x, int y = 0){
	unordered_set <int> con;
	int tx, ty;
 
	do{
		tx = st.top().first, ty = st.top().second;
		st.pop();
		con.insert(tx), con.insert(ty);
	}while(tx != x || ty != y);
	bcc.emplace_back(con);
}
 
void dfs(int v = 1, int p = 0){
	low[v] = tin[v] = tin[p] + 1;
 
	for(int to : gr[v]){
		if(to == p) continue;
 
		if(!tin[to]){
			st.push({v, to});
			dfs(to, v);
			low[v] = min(low[v], low[to]);
 
			if(low[to] >= tin[v])
				find_bcc(v, to);
		}
		else low[v] = min(low[v], tin[to]);
	}
}
 
void Print_bcc(){
	g << bcc.size() << "\n";
	for(int i = 0;i < (int)bcc.size();i++){
		for(int x : bcc[i])
			g << x << " ";
		g << "\n";
	}
}
 
 
int main(){
	Read();
	dfs(1, 0);
	Print_bcc();
}