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

using namespace std;
const int NMAX = 100002;

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

vector <vector <int>> v, bicon;
stack <int> s;
int niv[NMAX]; ///depth (basically dist fata de rad)
int h[NMAX];
bitset <NMAX> f;

void dfs(int start, int tata) {
    s.push(start);
    f[start] = 1;
    for(auto nod : v[start]) {
        if(nod == tata)
            continue;
        if(f[nod]) { ///muchie de intoarcere
            h[start] = min(h[start], niv[nod]);
            continue;
        }
        niv[nod] = niv[start] + 1;
        h[nod] = niv[start] + 1;
        dfs(nod, start);
        h[start] = min(h[start], h[nod]);

        if(h[nod] >= niv[start]) { ///NU se poate ajunge mai sus, gg well played
            bicon.push_back(vector<int>());
            while(!s.empty() && s.top() != nod) {
                bicon.back().push_back(s.top());
                s.pop();
            }
            bicon.back().push_back(nod);
            bicon.back().push_back(start);
            s.pop();
        }
    }
}

int main()
{
    int n, m;
    cin >> n >> m;
    v.resize(n + 1);
    for(int i = 1; i <= m; i++) {
        int a, b;
        cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    niv[1] = 0, h[1] = 0;
    dfs(1, 0);
    cout << bicon.size() << '\n';
    for(int i = 0; i < bicon.size(); i++) {
        for(auto x : bicon[i])
            cout << x << " ";
        cout << '\n';
    }
    return 0;
}