#include<cstdio>
#include<vector>
#include<set>
#include<stack>
#define NMAX 100001
#define min(a,b) (a>b?b:a)
using namespace std;
struct per
{
    int l,r;
};
vector<int>v[NMAX];
stack<per>st;
set<int>s[NMAX];
bool viz[NMAX];
int n,m,i,x,y,low[NMAX],cbc=0;
per pereche(int t,int p)
{
    per X;X.l=t;X.r=p;
    return X;
}
void dfs(int nod,int niv,int tata)
{
    viz[nod]=1;
    low[nod]=niv;
    vector<int>::iterator it;
    for(it=v[nod].begin();it!=v[nod].end();++it)
    {
        int fiu=*it;
        if (fiu==tata) continue;
        if (viz[fiu]==0)
        {
            st.push(pereche(nod,fiu));
            dfs(fiu,niv+1,nod);
            low[nod]=min(low[nod],low[fiu]);
            if (low[fiu]>=niv)
            {
                ++cbc;
                per X;
                do
                {
                    X=st.top();
                    st.pop();
                    s[cbc].insert(X.l);
                    s[cbc].insert(X.r);
                }while(X.l!=nod || X.r!=fiu);
            }
        }
        else low[nod]=min(low[nod],low[fiu]);
    }

}
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);
    }
    for (i=1;i<=n;++i)
    {
        if (viz[i]==0)
        {
            dfs(1,1,0);
        }
    }
    printf("%d\n",cbc);
    for (i=1;i<=cbc;++i)
    {
        set<int>::iterator it;
        for(it=s[i].begin();it!=s[i].end();++it)
               printf("%d ",*it);
        printf("\n");
    }
    return 0;
}