#include <iostream>
#include <cstdio>
#include <vector>
using namespace std;

vector <int > g[100005];
vector <int > st,sol[100005];
int n,m,low[100005],niv[100005],nrsol,k;

void citire()
{
    scanf("%d%d",&n,&m);
    for (int i=1;i<=m;++i)
    {
        int nod1,nod2;
        scanf("%d%d",&nod1,&nod2);
        g[nod1].push_back(nod2);
        g[nod2].push_back(nod1);
    }
}
void golire(int xnod)
{
    while (!st.empty() && st.back()!=xnod)
    {
        sol[nrsol].push_back(st.back());
        st.pop_back();
    }
    sol[nrsol].push_back(st.back());
    nrsol++;
}
void dfs(int nod,int tata)
{
    low[nod]=niv[tata]+1;
    niv[nod]=niv[tata]+1;
    st.push_back(nod);
    for (vector <int > :: iterator it=g[nod].begin();it!=g[nod].end();++it)
    {
        if (!niv[*it])
        {
            ///if (nod==1)
               /// ++k;
            dfs(*it,nod);
            if (low[*it]<low[nod])
                low[nod]=low[*it];
            if(niv[nod]<=low[*it])
                golire(nod);
        }
        else if (*it!=tata && niv[*it]<low[nod])
            low[nod]=niv[*it];
    }
}
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    citire();
    dfs(1,0);
    printf("%d\n",nrsol);
    for (int i=0;i<nrsol;++i)
    {
        vector <int > ::iterator it;
        for (it=sol[i].begin();it!=sol[i].end();++it)
            printf("%d ",*it);
        printf("\n");
    }
    return 0;
}