#include <cstdio>
#include <vector>
#include <stack>
#include <algorithm>

using namespace std;

stack< pair<int, int > > st;
vector< vector<int> > sol;
vector<int> g[100002];
int index[100002], lowlink[100002];
int counter = 0;

void addSol(int a, int b)
{
    vector<int> v;
    int x = 0, y = 0;
    do
    {
        x = st.top().first;
        y = st.top().second;
        st.pop();
        v.push_back(x);
        v.push_back(y);
    } while (x != a && y != b);
    sol.push_back(v);
}

void biconex(int node, int parent)
{
    index[node] = lowlink[node] = ++counter;
    for (unsigned i = 0; i < g[node].size(); i++)
        if (g[node][i] != parent)
        {
            if (index[g[node][i]] == 0)
            {
                st.push(make_pair(node, g[node][i]));
                biconex(g[node][i], node);
                lowlink[node] = min(lowlink[node], lowlink[g[node][i]]);
                if (lowlink[g[node][i]] >= index[node])
                    addSol(node, g[node][i]);
            }
            else
                lowlink[node] = min(lowlink[node], index[g[node][i]]);
        }
}

int main()
{
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);

    int n, m;
    scanf("%d%d", &n, &m);

    for (int i = 1, x, y; i <= m; i++)
    {
        scanf("%d%d", &x, &y);
        g[x].push_back(y);
        g[y].push_back(x);
    }

    for (int i = 1; i <= n; i++)
        if (index[i] == 0)
            biconex(i, 0);

    printf("%d\n", sol.size());
    for (unsigned i = 0; i < sol.size(); i++)
    {
        sort(sol[i].begin(), sol[i].end());
        printf("%d", sol[i][0]);
        for (unsigned j = 1; j < sol[i].size(); j++)
            if (sol[i][j] != sol[i][j-1])
                printf(" %d", sol[i][j]);
        printf("\n");
    }

    return 0;
}