#include <stdio.h>
#include <vector>
#include <stack>
using namespace std;
int n,m,i,x,y,niv[100001],j[100001],t,T[100001];
bool o[100001];
int k;
vector<int> G[100001],c[100001];
stack<int> stiva;
void afis(int s)
{
    t++;
    for (int i=stiva.top();i!=s;stiva.pop(),i=stiva.top())
        c[t].push_back(i);
    c[t].push_back(s);
}
void DFS(int s)
{
    int i,z=G[s].size();
    o[s]=1; stiva.push(s); j[s]=niv[s];
    for (i=0;i<z;i++)
        if (!o[G[s][i]])
    {
        niv[G[s][i]]=niv[s]+1;
        T[G[s][i]]=s;
        DFS(G[s][i]);
        j[s]=min(j[s],j[G[s][i]]);
        if (j[G[s][i]]>=niv[s]) afis(s);
    }
    else
    {
        if (G[s][i]!=T[s])
        j[s]=min(j[s],j[G[s][i]]);
    }
}
int main()
{
    freopen ("biconex.in","r",stdin);
    freopen ("biconex.out","w",stdout);
    scanf("%i%i",&n,&m);
    for (i=1;i<=m;i++)
    {
        scanf("%i%i",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1);
    printf("%i\n",t);
    for (i=1;i<=t;i++,printf("\n"))
        for (k=0;k<c[i].size();k++) printf("%i ",c[i][k]);
    fclose(stdin);
    fclose(stdout);
    return 0;
}