#include <bits/stdc++.h>

using namespace std;

const int MaxN=100010;
vector<int> g[MaxN];
vector<pair<int,int> > q;
vector<vector<int> > comp;
int niv[MaxN],nivmin[MaxN];
char vaz[MaxN];

void comp_biconexa(int x,int y)
{
	int a,b;
	comp.push_back(vector<int>());
	do
	{
		a=q.back().first;
		b=q.back().second;
		q.pop_back();
		comp.back().push_back(b);
	}while(a!=x || b!=y);
	comp.back().push_back(x);
}

void dfs(int nod,int lev)
{
	niv[nod]=nivmin[nod]=lev;
	vaz[nod]=1;
	for(auto vec : g[nod])
		if(!vaz[vec])
		{
			q.push_back({nod,vec});
			dfs(vec,lev+1);
			nivmin[nod]=min(nivmin[nod],nivmin[vec]);
			if(nivmin[vec]>=niv[nod]) comp_biconexa(nod,vec);
		}
		else nivmin[nod]=min(nivmin[nod],niv[vec]);
}

int main()
{
	freopen("biconex.in", "r", stdin);
	freopen("biconex.out", "w", stdout);
	int n,m,x,y;
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;i++)
	{
		scanf("%d%d",&x,&y);
		g[x].push_back(y);
		g[y].push_back(x);
	}
	for(int i=1;i<=n;i++)
		if(!vaz[i]) dfs(i,0);
	printf("%d\n",comp.size());
	for(int i=0;i<comp.size();i++)
	{
		for(int j=0;j<comp[i].size();j++) printf("%d ",comp[i][j]);
		printf("\n");
	}
	return 0;
}