#include<stdio.h>
#include<vector>
#define MAXN 100005

using namespace std;

int n,m,i,j,u,nrc,x,y;
int level[MAXN],c[MAXN],v[MAXN];
int stx[MAXN],sty[MAXN];
vector <int> sol[MAXN];
vector <int> a[MAXN];

void adaug(int a,int b)
{
    int x,y;
    nrc++;
    do
    {
        x=stx[u];
        y=sty[u--];
        sol[nrc].push_back(y);
    }
    while(x!=a || y!=b);
    sol[nrc].push_back(x);
}

void df(int nod,int tata)
{
    int i,nnod;
    level[nod]=level[tata]+1;
    c[nod]=level[nod];
    v[nod]=1;

    for(i=0;i<a[nod].size();i++)
    {
        nnod=a[nod][i];
        if(!v[nnod])
        {
            stx[++u]=nod;
            sty[u]=nnod;
            df(nnod,nod);
            if(c[nnod] < c[nod])
                c[nod]=c[nnod];
            if(c[nnod] >= level[nod])
                adaug(nod,nnod);
        }
        else
        if(nnod!=tata && c[nnod] < c[nod])
            c[nod]=c[nnod];
    }
}


int main(void)
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    scanf("%d%d",&n,&m);
    while(m--)
    {
        scanf("%d%d",&x,&y);
        a[x].push_back(y);
        a[y].push_back(x);
    }
    df(1,0);
    printf("%d\n",nrc);
    for(i=1;i<=nrc;i++)
    {
        for(j=0;j<sol[i].size();j++)
            printf("%d ",sol[i][j]);
        printf("\n");
    }
    return 0;
}