#include <bits/stdc++.h>
#define ff first
#define ss second

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;

const string file = "biconex";
const ll INF = 9223372036854775807ll;
const int inf = 2147483647, nmax = 100005;

int n, m, dfn[nmax], low[nmax], nrfii, p;
vector<int> v[nmax];
vector< vector<int> > sol;
stack<pi> s;
bool ok[nmax];

void add_sol(int x, int y)
{
    sol.push_back(vector<int>());
    unordered_set<int> r;
    pi now;
    do{
        now = s.top();
        s.pop();
        r.insert(now.ff);
        r.insert(now.ss);
    }while((x != now.ff || y != now.ss) && (x != now.ss || y != now.ff));
    for (auto x : r)
        sol.back().push_back(x);
}

void dfs(int x)
{
    ok[x] = 1;
    dfn[x] = ++p;
    low[x] = dfn[x];
    for (auto y : v[x])
        if(!ok[y]){
            s.push({x, y});
            dfs(y);
            low[x] = min(low[x], low[y]);
            if(low[y] >= dfn[x])
                add_sol(x, y);
        }else low[x] = min(low[x], dfn[y]);
}

int main()
{
    ifstream fin (file+".in");
    ofstream fout (file+".out");
    fin >> n >> m;
    for (int i = 1; i <= m; ++i){
        int x, y;
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1);
    fout << sol.size() << "\n";
    for (auto x : sol){
        for (auto y : x)
            fout << y << " ";
        fout << "\n";
    }
    return 0;
}