#include <stdio.h>
#include <vector>
#include <algorithm>
#define max 100010
using namespace std;
int n,m,i,j,preord[max],nivmin[max],stack[max*2],top,timp,comp;
char s[max];
vector<int> compc[max],g[max];
void add(int v,int w)
{
    int i,j;
    vector<int> aux;
    comp++;
    do
    {
        j=stack[top--]; i=stack[top--];
        aux.push_back(i);
        aux.push_back(j);
    }
    while(i!=v || j!=w);
    sort(aux.begin(),aux.end());
    compc[comp].push_back(aux[0]);
    for(i=1; i<aux.size(); i++)
     if(aux[i]!=aux[i-1])
      compc[comp].push_back(aux[i]);
}
void dfs(int v)
{
    int i;
    s[v]=1;
    preord[v]=nivmin[v]=++timp;
    for(i=0; i<g[v].size(); i++)
    {
        if(!s[g[v][i]])
        {
            stack[++top]=v;
            stack[++top]=g[v][i];
            dfs(g[v][i]);
            if(nivmin[g[v][i]]>=preord[v]) add(v,g[v][i]);
            nivmin[v]=min(nivmin[v],nivmin[g[v][i]]);
        }
        else
         nivmin[v]=min(nivmin[v],preord[g[v][i]]);
    }
}
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(; m>0; m--)
    {
        scanf("%d%d",&i,&j);
        g[i].push_back(j);
        g[j].push_back(i);
    }
    for(i=1; i<=n; i++)
     if(!s[i])
     {
         timp=0;
         dfs(i);
     }
    printf("%d\n",comp);
    for(i=1; i<=comp; i++)
    {
        for(j=0; j<compc[i].size(); j++)
         printf("%d ",compc[i][j]);
        printf("\n");
    }
    return 0;
}