#include <bits/stdc++.h>
#define NMAX 100001
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,biconex;
vector< int > v[NMAX],sol[NMAX];
int fr[NMAX],dm[NMAX],niv[NMAX];
deque<int >q;
void dfs(int k, int tata)
{
    niv[k]=niv[tata]+1;;
    fr[k]=1;
    q.push_back(k);
    dm[k]=niv[k];
    for(auto x : v[k])
    {
        if(x==tata)continue;
        if(fr[x])
        {
            dm[k]=dm[k]<niv[x]? dm[k] : niv[x];
            continue;
        }
        dfs(x,k);
        dm[k]= dm[k] < dm[x] ? dm[k] : dm[x];
        if(niv[k]<=dm[x])
        {
            ++biconex;
            int t;
            do
            {
                t=q.back();
                q.pop_back();
                sol[biconex].push_back(t);
            }while(!q.empty()&&t!=x);
            sol[biconex].push_back(k);
        }
    }
}
int main()
{
    fin>>n>>m;
    for(int i=1;i<=m;++i)
    {
        int x,y;
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0);
    fout<<biconex<<"\n";
    for( int i=1;i<=biconex;++i, fout<<"\n")
        for( auto x :sol[i])fout<<x<<" ";
    return 0;
}