#include <cstdio>
#include <vector>
#include <stack>
#include <set>
#include <algorithm>
#define SIZE 100001
using namespace std;

int n, m, i, j, x, y, nr;
vector <int> adj[SIZE], dfn, low;
stack < pair <int, int> > st;
set <int> sol[SIZE];

void calc_sol(int father_node, int node)
{
    ++nr;
    do
    {
        x=st.top().first; y=st.top().second;
        sol[nr].insert(x); sol[nr].insert(y);
        st.pop();
    } while(x!=father_node || y!=node);
}

void DFS(int node, int num)
{
    low[node]=dfn[node]=num;

    for(vector <int> :: iterator it=adj[node].begin(); it!=adj[node].end(); ++it)
        if(dfn[*it]==-1)
        {
            st.push(make_pair(node, *it));
            DFS(*it, num+1);
            low[node]=min(low[node], low[*it]);
            if(low[*it]>=dfn[node])
                calc_sol(node, *it);
        }
        else
            low[node]=min(low[node], dfn[*it]);
}

int main()
{
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    scanf("%d %d", &n, &m);
    while(m--)
    {
        scanf("%d %d", &x, &y);
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    dfn.resize(n+1); dfn.assign(n+1, -1);
    low.resize(n+1);
    DFS(1, 0);
    printf("%d\n", nr);
    for(i=1;i<=nr;++i)
    {
        for(set <int> :: iterator it=sol[i].begin(); it!=sol[i].end(); ++it)
            printf("%d ", *it);
        printf("\n");
    }
    return 0;
}