#include <iostream>
#include <vector>
#include <stack>
#include <set>
#include <cstdio>
#define mp make_pair
#define pb push_back

using namespace std;

const int N = 100005;

int n,m,cbc,viz[N],niv[N];

vector<int> a[N];
set<int> sol[N];
stack< pair<int,int> > st;
set<int>::iterator it;

void dfs(int nod,int nivel,int tata)
{
    int i,fiu;
    viz[nod]=1;
    niv[nod]=nivel;
    for(i=0;i<a[nod].size();i++)
    {
        fiu=a[nod][i];
        if(fiu==tata)
            continue;
        if(viz[fiu]==0)
        {
            st.push(mp(nod,fiu));
            dfs(fiu,nivel+1,nod);
            niv[nod]=min(niv[nod],niv[fiu]);
            if(niv[fiu]>=nivel)
            {
                ++cbc;
                int x,y;
                do
                {
                    x=st.top().first;
                    y=st.top().second;
                    st.pop();
                    sol[cbc].insert(x);
                    sol[cbc].insert(y);
                }
                while(x!=nod && y!=fiu);
            }
        }
        else
            niv[nod]=min(niv[nod],niv[fiu]);
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    scanf("%d %d",&n,&m);
    int i,x,y;
    for(i=1;i<=m;i++)
    {
        scanf("%d %d",&x,&y);
        a[x].pb(y);
        a[y].pb(x);
    }
    for(i=1;i<=n;i++)
        if(viz[i]==0)
            dfs(i,1,0);
    printf("%d\n",cbc);
    for(i=1;i<=cbc;i++)
    {
        for(it=sol[i].begin();it!=sol[i].end();++it)
            printf("%d ",*it);
        printf("\n");
    }
    return 0;
}