#include<stdio.h>
#include<vector>
#include<stack>
#include<algorithm>
#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,x,y;
int viz[maxn],niv[maxn],low[maxn];
vector<int>G[maxn],v;
vector< vector<int> >Sol;
stack< pair<int,int> >St;

inline void citire () {
	
	fscanf(f,"%d %d",&n,&m);
	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());
	Sol.pb(v);
}

void dfs ( int nod , int t ){
	viz[nod] = 1; niv[nod] = low[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);
			if ( low[nodvcn] < low[nod] )
				low[nod] = low[nodvcn];
			if ( low[nodvcn] >= niv[nod] ){
				componenta(nod,nodvcn);
			}
		}
		else{
			if ( low[nod] > niv[nodvcn] ){
				low[nod] = niv[nodvcn];
			}
		}
	}
}


int main () {
	fscanf(f,"%d %d",&n,&m);
	for ( int i = 1 ; i <= m ; ++i ){
		fscanf(f,"%d %d",&x,&y);
		G[x].pb(y);
		G[y].pb(x);
	}
	dfs(1,0);
	fprintf(g,"%d\n",Sol.size());
	for (int i = 0 ; i < Sol.size() ; ++i ){
		for ( vector<int>::iterator itt = Sol[i].begin() ; itt != Sol[i].end() ; ++itt ){
			fprintf(g,"%d ",(*itt));
		}
		fprintf(g,"\n");
	}
	fclose(f);
	fclose(g);
	
	return 0;
}