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

#define maxn 100005

using namespace std;

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

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

inline void componenta ( int x , int y ){
	v.clear();
	int nod1,nod2;
	
	do{
		nod1 = st.top().first,nod2 = st.top().second;
		st.pop();
		v.push_back(nod1); v.push_back(nod2);
	}while( nod1 != x || nod2 != y );
	
	sort(v.begin(),v.end());
	v.resize(unique(v.begin(),v.end())-v.begin());
	
	C.push_back(v);
}

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

int main () {
	
	fscanf(f,"%d %d",&n,&m);
	int x,y;
	for ( int i = 1 ; i <= m ; ++i ){
		fscanf(f,"%d %d",&x,&y);
		G[x].push_back(y);
		G[y].push_back(x);
	}
	
	for ( int i = 1 ; i <= n ; ++i ){
		if ( !viz[i] ){
			dfs(i);
		}
	}
	
	fprintf(g,"%d\n",C.size());
	for ( int i = 0 ; i < C.size() ; ++i ){
		for ( int j = 0 ; j < C[i].size() ; ++j ){
			fprintf(g,"%d ",C[i][j]);
		}
		fprintf(g,"\n");
	}
	
	fclose(f);
	fclose(g);
	
	return 0;
}