#include <cstdio>
#include <vector>
using namespace std;
vector<int> v[100007];
vector<vector<int> > comp;
vector<pair<int,int> > q;
int niv[100007],nivmin[100007];
char vaz[100007];
void compbiconex(int a,int b)
{
    vector<int> aux;
    int x,y;
    do
    {
        x=q.back().first;
        y=q.back().second;
        q.pop_back();
        aux.push_back(y);
    }
    while(a!=x || b!=y);
    aux.push_back(a);
    comp.push_back(aux);
}
void dfs(int nod,int lev)
{
    vaz[nod]=1;
    niv[nod]=nivmin[nod]=lev;
    for(vector<int>::iterator it=v[nod].begin(); it!=v[nod].end(); it++)
        if(!vaz[*it])
        {
            q.push_back({nod,*it});
            dfs(*it,lev+1);
            nivmin[nod]=min(nivmin[nod],nivmin[*it]);
            if(nivmin[*it]>=niv[nod]) compbiconex(nod,*it);
        }
        else nivmin[nod]=min(nivmin[nod],niv[*it]);
}
int main()
{
    freopen("biconex.in","r", stdin);
    freopen("biconex.out","w", stdout);
    int n,m,x,y;
    scanf("%d%d",&n,&m);
    for(int i=1; i<=m; i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i=1; i<=n; i++)
        if(!vaz[i]) dfs(i,0);
    printf("%d\n",comp.size());
    for(int i=0; i<comp.size(); i++)
    {
        for(int j=0; j<comp[i].size(); j++) printf("%d ",comp[i][j]);
        printf("\n");
    }
    return 0;
}