#include <fstream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <stack>
#define nmax 100010

using namespace std;

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

bool use[nmax];
stack <int> stk;
vector <int> ans[nmax],v[nmax];
int nrcb,n,m,i,low[nmax],nivel[nmax];

void dfs(int x)
{
    use[x]=1;
    stk.push(x);
    for (int i=0; i<v[x].size(); i++)
    {
        int vecin=v[x][i];
        if (use[vecin])
            low[x]=min(low[x],nivel[vecin]);
        else
        {
            low[vecin]=nivel[x];
            nivel[vecin]=nivel[x]+1;
            dfs(vecin);
            if (low[vecin]==nivel[x])
            {
                ++nrcb;
                while (stk.top()!=vecin)
                {
                    ans[nrcb].push_back(stk.top());
                    stk.pop();
                }
                ans[nrcb].push_back(stk.top());
                stk.pop();
                ans[nrcb].push_back(x);
            }
            low[x]=min(low[x],low[vecin]);
        }
    }
}

int main()
{
    fin >> n >> m;
    for (i=1; i<=m; i++)
    {
        int a,b;
        fin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (i=1; i<=n; i++)
        if (!use[i])
            dfs(i);
    fout << nrcb << '\n';
    for (i=1; i<=nrcb; i++)
    {
        for (int j=0; j<ans[i].size(); j++)
            fout << ans[i][j] << ' ';
        fout << '\n';
    }
}