#include <fstream>
#include <vector>

using namespace std;

ifstream in ("biconex.in");
ofstream out("biconex.out");

const int Max = 100010;

vector<int> v[Max];
vector<vector<int> > comp;
vector<pair<int, int> > q;
int niv[Max], nivMin[Max];
char vaz[Max];

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()
{
    int n, m, x, y;
    in >> n >> m;
    for(int i = 1; i <= m; ++i)
    {
        in >> 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);
    }
    out << comp.size() << "\n";

    for(int i = 0; i < comp.size(); ++i)
    {
        for(int j = 0; j < comp[i].size(); ++j)
        {
            out << comp[i][j] << " ";
        }

        out << "\n";
    }

    return 0;
}