#include <fstream>
#include <vector>
#include <stack>

using namespace std;

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

const int nmax = 100000;

vector <int> g[nmax+1];

int level;
int l[nmax+1], ll[nmax+1], f[nmax+1];
stack <int> s;

vector < vector <int> > sol;

void dfs( int x ) {
    ++ level;
    l[x] = level;
    ll[x] = level;
    s.push(x);

    for ( int i = 0; i < int(g[x].size()); ++ i ) {
        int xn = g[x][i];
        if ( xn != f[x] ) {
            if ( l[xn] == 0 ) {
                dfs(xn);
                if ( ll[xn] < l[x] ) {
                    ll[x] = ll[xn];
                } else {
                    int nsol = sol.size()+1;
                    sol.resize(nsol);
                    sol[nsol-1].resize(0);
                    while ( s.top() != xn ) {
                        sol[nsol-1].push_back(s.top());
                        s.pop();
                    }
                    s.pop();
                    sol[nsol-1].push_back(xn);
                    sol[nsol-1].push_back(x);
                }
            } else {
                if ( l[xn] < ll[x] ) {
                    ll[x] = l[xn];
                }
            }
        }
    }
}

int main( ) {
    int n, m;
    fin >> n >> m;
    for ( int i = 1; i <= m; ++ i ) {
        int x, y;
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }

    for ( int i = 1; i <= n; ++ i ) {
        if ( l[i] == 0 ) {
            dfs(i);
            while ( s.empty() == 0 ) {
                s.pop();
            }
        }
    }

    fout << sol.size() << "\n";
    for ( int i = 0; i < int(sol.size()); ++ i ) {
        for ( int j = 0; j < int(sol[i].size()); ++ j ) {
            fout << sol[i][j] << " ";
        }
        fout << "\n";
    }

    return 0;
}