#include<fstream>
#include<vector>
#include<stack>
#define inf "biconex.in"
#define outf "biconex.out"
#define NMax 100100
#define MMax 200100
using namespace std;

fstream f(inf,ios::in),g(outf,ios::out);

vector<int> LA[NMax];
vector< vector<int> > C;
stack< pair<int,int> > S;
int N, M, dfn[NMax], low[NMax], nr;

inline int min(int a,int b) { return ( a<b ? a : b ); }

void read()
{
	f>>N>>M; int a,b;
	for(int i=1; i<=M; i++)
	{
		f>>a>>b;
		LA[a].push_back(b); LA[b].push_back(a);
	}
}

void cache(int u,int tu)
{
	int x,y; vector<int> v;
	do
	{
		x = S.top().first; y = S.top().second;
		S.pop();
		v.push_back(x); v.push_back(y);
	}
	while( x!=u || y!=tu );
	C.push_back(v);
}

void DFS(int u, int tu)
{
	dfn[u] = low[u] = ++nr;
	for(int i=0; i<LA[u].size(); i++)
	{
		int v = LA[u][i];
		if( v==tu ) continue;
		if( !dfn[v] )
		{
			S.push( make_pair(u,v) );
			DFS( v,u );
			low[u] = min( low[u], low[v] );
			if( low[v]>=dfn[u] ) cache(u,v);
		}
		else  low[u] = min(low[u], dfn[v]);
	}
}

void solve()
{
	DFS(1,-1);
	g<< C.size() <<"\n";
	for(int i=0; i<C.size(); i++)
	{
		for(int j=0; j<C[i].size(); j++) g<< C[i][j] <<" ";
		g<<"\n";
	}
}

int main()
{
	read(); solve();
	f.close(); g.close();
	return 0;
}