//horatiu11
# include <cstdio>
# include <vector>
# include <algorithm>
# include <stack>
# include <set>
# define nmax 100001
using namespace std;
int n,m,x,y,nr,lg[nmax],niv[nmax];
bool viz[nmax];
vector <int>G[nmax],rez[nmax];
stack < pair<int,int> >st;
inline void rezultat(int x, int y)
{
    int aux1,aux2;
    do
    {
        aux1=st.top().first;
        aux2=st.top().second;
        rez[nr].push_back(aux1);
        rez[nr].push_back(aux2);
        st.pop();
    }while(x != aux1 || y != aux2);
}
void dfs(int x, int father)
{
    vector <int>::iterator it;
    viz[x]=true;
    niv[x]=niv[father]+1;
    lg[x]=niv[x];
    for(it=G[x].begin();it!=G[x].end();++it)
        if(*it==father)continue;
        else if(!viz[*it])
        {
            st.push(make_pair(x,*it));
            dfs(*it,x);
            lg[x]=min(lg[x],lg[*it]);
            if(lg[*it]>=niv[x])
            {
                nr++;
                rezultat(x,*it);
            }
        }
        else lg[x]=min(lg[x],niv[*it]);
}
int main()
{
    int i;
    vector <int>::iterator it;
    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);
        G[x].push_back(y);G[y].push_back(x);
    }
    for(i=1;i<=n;++i)
        if(!viz[i])
            dfs(i,0);
    printf("%d\n",nr);
    for(i=1;i<=nr;++i)
    {
        sort(rez[i].begin(),rez[i].end());
        rez[i].erase( unique(rez[i].begin(),rez[i].end()), rez[i].end());
        for(it=rez[i].begin();it!=rez[i].end();++it)
            printf("%d ",*it);
        printf("\n");
    }
    return 0;
}