#include<stdio.h>
#include<vector>
#include<algorithm>
#include<stack>

#define maxn 100005
#define pb push_back
#define mp make_pair

using namespace std;

FILE*f=fopen("biconex.in","r");
FILE*g=fopen("biconex.out","w");

int n,m;
int viz[maxn],niv[maxn],lowest[maxn];
vector<int>G[maxn],v;
vector< vector<int> >C;
stack< pair<int,int> >St;

inline void citire () {
	
	fscanf(f,"%d %d",&n,&m);
	
	int x,y;
	for ( int i = 1 ; i <= m ; ++i ){
		fscanf(f,"%d %d",&x,&y);
		G[x].pb(y);
		G[y].pb(x);
	}
}

inline void componenta ( int x , int y ){
	int nod1,nod2;
	v.clear();
	
	do{
		nod1 = St.top().first; nod2 = St.top().second;
		St.pop();
		v.pb(nod1); v.pb(nod2);
		
	}while(nod1!= x || nod2!=y);
	
	sort(v.begin(),v.end());
	vector<int>::iterator itt = unique(v.begin(),v.end());
	v.resize(itt-v.begin());
	
	C.pb(v);
}

void dfs ( int nod , int t ){
	viz[nod] = 1;
	niv[nod] = lowest[nod] = niv[t]+1;
	
	for ( vector<int>::iterator itt = G[nod].begin() ; itt != G[nod].end() ; ++itt ){
		int nodvcn = (*itt);
		if ( nodvcn == t )	continue ;
		
		if ( !viz[nodvcn] ){
			St.push(mp(nod,nodvcn));
			dfs(nodvcn,nod);
			
			lowest[nod] = min(lowest[nod],lowest[nodvcn]);
			if ( lowest[nodvcn] >= niv[nod] ){
				componenta(nod,nodvcn);
			}
		}
		else{
			lowest[nod] = min(lowest[nod],lowest[nodvcn]);
		}
	}
}

inline void biconex () {
	
	for ( int i = 1 ; i <= n ; ++i ){
		if ( !viz[i] ){
			dfs(i,0);
		}
	}
	
	fprintf(g,"%d\n",C.size());
	for ( int i = 0 ; i < C.size() ; ++i ){
		for ( vector<int>::iterator itt = C[i].begin() ; itt != C[i].end() ; ++itt ){
			fprintf(g,"%d ",*itt);
		}
		fprintf(g,"\n");
	}
}

int main () {
	
	citire();
	biconex();
	
	fclose(f);
	fclose(g);
	
	return 0;
}