#include <bits/stdc++.h>

using namespace std;

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

const int DIM = 100000 + 5;

vector < int > a[DIM];
vector < vector < int > > sol;
stack < pair < int, int > > st;

int disc[DIM], low[DIM], temp;

void found(int x, int y)
{
    vector < int > add;
    pair < int, int > top;
    do {
        top = st.top();
        add.push_back(top.first), add.push_back(top.second);
        st.pop();
    }
    while(top.first != x && top.second != y);
    sol.push_back(add);
}

void dfs(int k)
{
    disc[k] = low[k] = ++temp;
    for(auto v : a[k]) {
        if(disc[v] == 0) {
            st.push({k, v});
            dfs(v);
            low[k] = min(low[k], low[v]);
            if(low[v] >= disc[k]) found(k, v);
        }
        else low[k] = min(low[k], disc[v]);
    }
}

int main()
{
    int n, m;

    fin >> n >> m;
    for(int i = 1; i <= m; ++i) {
        int x, y;

        fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(int i = 1; i <= n; ++i) {
        if(disc[i] == 0) dfs(i);
    }
    fout << sol.size() << "\n";
    for(auto v : sol) {
        sort(v.begin(), v.end());
        v.erase(unique(v.begin(), v.end()), v.end());
        for(auto w : v) fout << w << " ";
        fout << "\n";
    }
    return 0;
}