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

using namespace std;

typedef pair<int,int> PII;
const int NMAX = 100000+5;

void Read(),DFS(int,int,int),Print();

int N,M,Nr_Biconex;
int Depth[NMAX];
int Low[NMAX];
vector<int> V[NMAX];
vector<int> Biconex[NMAX];
vector<int> S;

void Get_Biconex(int node,int son)
{
    Nr_Biconex++;
    while(S.back() != son)
    {
        Biconex[Nr_Biconex].push_back(S.back());
        S.pop_back();
    }
    Biconex[Nr_Biconex].push_back(node);
    Biconex[Nr_Biconex].push_back(son);
    S.pop_back();
}

int main()
{
    Read();
    DFS(1,1,0);
    Print();

    return 0;
}

void Read()
{
    int x,y;

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

    scanf("%d%d",&N,&M);

    for(; M; --M)
    {
        scanf("%d%d",&x,&y);
        V[x].push_back(y);
        V[y].push_back(x);
    }
}

void DFS(int node,int depth,int father)
{
    vector<int>::iterator it;

    Depth[node] = depth;
    Low[node] = depth;

    for(it = V[node].begin(); it != V[node].end(); it++)
    {
        if(*it == father) continue;
        if(!Depth[*it])
        {
            S.push_back(*it);
            DFS(*it,depth+1,node);
            if(Low[*it] >= Depth[node]) Get_Biconex(node,*it);
        }
        Low[node] = min(Low[node],Low[*it]);
    }
}

void Print()
{
    vector<int>::iterator it;
    int i;

    printf("%d\n",Nr_Biconex);

    for(i = 1; i <= Nr_Biconex; i++)
    {
        sort(Biconex[i].begin(),Biconex[i].end());
        for(it = Biconex[i].begin(); it != Biconex[i].end(); it ++)
            printf("%d ",*it);
        printf("\n");
    }
}