#include <fstream>
#include <algorithm>
#include <vector>
#include <stack>
#define ff first
#define ss second

using namespace std;

int n, m, dfn[100005], low[100005], num;
vector<int> v[100005];
vector< vector<int> > sol;
stack< pair<int, int> > q;

void add_sol(int x, int u)
{
    vector<int> r;int tx, ty;
    do{
        tx = q.top().ff, ty = q.top().ss;
        r.push_back(tx);
        r.push_back(ty);
        q.pop();
    }while(tx != x || ty != u);
    sol.push_back(r);
}

void dfs(int u, int tu)
{
    dfn[u] = low[u] = ++num;
    for (unsigned i = 0; i < v[u].size(); ++i){
        int x = v[u][i];
        if(x == tu)
            continue;
        if(dfn[x] == -1){
            q.push(make_pair(u, x));
            dfs(x, u);
            low[u] = min(low[u], low[x]);
            if(low[x] >= dfn[u])
                add_sol(u, x);
        }else low[u] = min(low[u], dfn[x]);
    }
}

int main()
{
    ifstream fin ("biconex.in");
    ofstream fout ("biconex.out");
    fin >> n >> m;
    while(m--){
        int x, y;
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (int i = 1; i <= n; ++i)
        dfn[i] = -1;
    dfs(1, -1);
    fout << sol.size() << "\n";
    for (unsigned i = 0; i < sol.size(); ++i){
        sort(sol[i].begin(), sol[i].end());
        fout << sol[i][0] << " ";
        for (unsigned j = 1; j < sol[i].size(); ++j)
            if(sol[i][j] != sol[i][j-1])
                fout << sol[i][j] << " ";
        fout << "\n";
    }
    fin.close();
    fout.close();
    return 0;
}