/*
    Those without power, seek us!
    Those with power, fear us!
    We are the Order of the Black Knights!
*/

#include<fstream>
#include<cstdio>
#include<map>
#include<set>
#define FIT(a,b) for(vector<int >::iterator a=b.begin();a!=b.end();a++)
#define FITP(a,b) for(vector<pair<int,int> >::iterator a=b.begin();a!=b.end();a++)
#define RIT(a,b) for(vector<int>::reverse_iterator a=b.end();a!=b.begin();++a)
#include<stack>
#define ROF(a,b,c) for(int a=b;a>=c;--a)
#include<vector>
#include<algorithm>
#define FOR(a,b,c) for(int a=b;a<=c;++a)
#define REP(a,b) for(register int a=0;a<b;++a)
#include<cstring>
#include<ctime>
#include<bitset>
#include<cmath>
#include<iomanip>
#include<set>
#define f cin
#define g cout
#include<queue>
#define debug cerr<<"OK";
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define ll long long
#define ull unsigned int
#define mod 1000000009LL
#define SQR 350
#define db double
#define inf 1<<30
#define div fdasfasd
#define hash dsafdsfds
#define od 100003
#define mod 666013
#define DIM 60010000
#define base 256
#define bas 255
#define N 120100
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
/*
    int dx[]={0,0,0,1,-1};
    int dy[]={0,1,-1,0,0};
*/
vector<int> v[N],B[N];
int n,m,x,y,low[N],niv[N],bi,s[N],t;
void dfs(int x,int lvl,int p)
{
    niv[x]=low[x]=lvl;
    s[++t]=x;
    FIT(it,v[x])
    if(*it!=p)
    {
        if(!niv[*it])
        {
            dfs(*it,lvl+1,x);
            if(low[*it]>=niv[x])
            {
                ++bi;
                while(s[t]!=x)
                    B[bi].pb(s[t--]);
                B[bi].pb(x);
            }
            else
                low[x]=min(low[x],low[*it]);
        }
        else
            low[x]=min(low[x],niv[*it]);
    }
}
int main ()
{
    f>>n>>m;
    FOR(i,1,m)
    {
        f>>x>>y;
        v[x].pb(y);
        v[y].pb(x);
    }
    dfs(1,1,0);
    g<<bi<<"\n";
    FOR(i,1,bi)
    {
    FIT(it,B[i])
    g<<*it<<" ";
    g<<"\n";
    }
    return 0;
}