#include<cstdio>
#include<vector>

int n,m,i,viz[100001],poz[100001],lvl=1,st[100001],top=0;
::std::vector<int> a[100001];
int nc;
::std::vector<int> c[100001];

int DF(int v,int niv)
{
	if(viz[v])
		return viz[v];

	int minlvl=niv,min2,till;
	viz[v] = niv;
	poz[v] = lvl++;
	st[++top] = v;

	for(int i = 0;i < a[v].size(); ++i)
	{
		till = lvl;
		min2 = DF(a[v][i],niv+1);
		if(min2>=niv)
		{
			++nc;
			while(poz[st[top]]>=till)
			{
				c[nc].push_back(st[top]);
				--top;
			}
			if(c[nc].size())
				c[nc].push_back(v);
			else
				--nc;
		}
		if(min2<minlvl)
			minlvl = min2;
	}
	return minlvl;
}

int main()
{
	freopen("biconex.in","r",stdin);
	freopen("biconex.out","w",stdout);
	scanf("%d %d",&n,&m);
	for(int x,y;m;--m)
	{
		scanf("%d %d",&x,&y);
		a[x].push_back(y);
		a[y].push_back(x);
	}
	for(i=1;i<=n;++i)
		if(!viz[i])
			DF(i,1);
	printf("%d\n",nc);
	for(int j,i=1;i<=nc;++i)
	{
		for(j=0;j<c[i].size();++j)
			printf("%d ",c[i][j]);
		printf("\n");
	}
	fclose(stdout);
	return 0;
}