#include<stdio.h>
#include<vector>
#define Nmx 200001

using namespace std;

int n,m,nr,u,st1[Nmx],st2[Nmx],c[Nmx],lv[Nmx],fol[Nmx];
vector <int> a[Nmx];
vector <int> sol[Nmx];

void citire()
{
    int x,y;
    scanf("%d %d ",&n,&m);
    for(int i=1;i<=m;++i)
    {
        scanf("%d %d",&x,&y);
        a[x].push_back(y);
        a[y].push_back(x);
    }
}

void add(int a,int b)
{
    int x,y;
    nr++;
    do
    {
        x=st1[u];
        y=st2[u--];
        sol[nr].push_back(y);
    }
    while(x!=a || y!=b);
    sol[nr].push_back(x);
}


void dfs(int nod,int tata)
{
    lv[nod]=lv[tata]+1;
    c[nod]=lv[nod];
    fol[nod]=1;
    int x,i;
    for(i=0;i<a[nod].size();++i)
    {
        x=a[nod][i];
        if(!fol[x])
        {
            st1[++u]=nod;
            st2[u]=x;
            dfs(x,nod);
            if(c[x]<c[nod])
              c[nod]=c[x];
            if(c[x]>=lv[nod])
              add(nod,x);
        }
        else if(x!=tata&&c[x]<c[nod])
           c[nod]=c[x];
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    citire();
    dfs(1,0);
    printf("%d\n",nr);
    for(int i=1;i<=nr;++i)
    {
        for(int j=0;j<sol[i].size();++j)
           printf("%d ",sol[i][j]);
        printf("\n");
    }
    return 0;
}