#include <cstdio>
#include <vector>
#include <algorithm>

using namespace std;
struct muchii
{
    int x,y;
}stiva[100010];
vector<int>v[100010],sol[100010];
vector<int>::iterator it;
int lev[100010],minlev[100010],n,m,i,x,y,nrsol,nr,dist;

void compbiconexa(int x,int y)
{
    int a,b;
    nrsol++;
    do
    {
        a=stiva[nr].x;
        b=stiva[nr--].y;
        sol[nrsol].push_back(b);
    }while(!(a==x && b==y));
    sol[nrsol].push_back(a);
}

void dfs(int nod,int tata)
{
    vector<int>::iterator it;
    int x;
    lev[nod]=minlev[nod]=++dist;
    for(it=v[nod].begin();it!=v[nod].end();it++)
    {
        if(*it==tata) continue;
        if(!lev[*it])
        {
            stiva[++nr].x=nod;
            stiva[nr].y=*it;
            dfs(*it,nod);
            minlev[nod]=min(minlev[nod],minlev[*it]);
            if(lev[nod]<=minlev[*it]) compbiconexa(nod,*it);
        }
        else minlev[nod]=min(minlev[nod],lev[*it]);
    }
}

int main()
{
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0);
    printf("%d\n",nrsol);
    for(i=1;i<=nrsol;i++)
    {
        for(it=sol[i].begin();it!=sol[i].end();it++) printf("%d ",*it);
        printf("\n");
    }
    return 0;
}