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

#define Nmax 100005

using namespace std;
int N,M,nrb;
vector<int> G[Nmax],bic[Nmax];
stack<int> S;
int nivel[Nmax],low[Nmax];

void read()
{
    scanf("%d%d",&N,&M);
    int a,b;
    for(int i = 1; i <= M; ++i)
    {
        scanf("%d%d",&a,&b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
}

void afisare(int n)
{
    ++nrb;
    while(S.top() != n)
    {
        bic[nrb].push_back(S.top());
        S.pop();
    }
    bic[nrb].push_back(n);
    S.pop();
}

void DFS(int k,int daddy)
{
    nivel[k] = nivel[daddy] + 1;
    low[k] = nivel[k];
    for(vector<int>::iterator it = G[k].begin(); it != G[k].end(); ++it)
        if(nivel[*it] == 0)
        {
            S.push(*it);
            DFS(*it,k);
            low[k] = min(low[k],low[*it]);
            if(nivel[k] <= low[*it])
            {
                afisare(*it);
                bic[nrb].push_back(k);
            }
        }
        else
            if( nivel[*it] < low[k] && *it != daddy )
                low[k] = nivel[*it];
}

void print()
{
    printf("%d\n",nrb);
    for(int i = 1; i <= nrb; ++i)
    {
        for(vector<int>::iterator it = bic[i].begin(); it != bic[i].end(); ++it)
            printf("%d ",*it);
        printf("\n");
    }
}

void solve()
{
    for(int i = 1; i <= N; ++i)
    {
        S.push(i);
        DFS(i,0);
        S.pop();
    }
}

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

    read();
    solve();
    print();

    return 0;
}