#include <bits/stdc++.h>
#define maxN 100010
using namespace std;
vector<int>v[maxN];
stack<pair<int,int> >stk;
vector<int>comp[maxN];
int n,m,i,j,low[maxN],lvl[maxN],nrcomp=0,x,y;
bool viz[maxN];
void biconex(int nod1,int nod2)
{
    nrcomp++;
    while(stk.top().first!=nod1 && stk.top().second!=nod2)
    {
        comp[nrcomp].push_back(stk.top().second);
        stk.pop();
    }
    comp[nrcomp].push_back(nod2);
    comp[nrcomp].push_back(nod1);
    stk.pop();
}
void dfs(int nod,int tata)
{
    lvl[nod]=low[nod]=lvl[tata]+1;
    viz[nod]=true;
    for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
    {
        if(!viz[*it])
        {
            stk.push(make_pair(nod,*it));
            dfs(*it,nod);
            if(low[nod]<low[*it])
                biconex(nod,*it);
        }
        if((*it)!=tata)
            low[nod]=min(low[nod],low[*it]);
    }
}
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    scanf("%d %d",&n,&m);
    for(i=1;i<=m;i++)
        scanf("%d %d",&x,&y),
        v[x].push_back(y),
        v[y].push_back(x);
    dfs(1,0);
    printf("%d\n",nrcomp);
    for(i=1;i<=nrcomp;i++,printf("\n"))
        for(j=0;j<(int)comp[i].size();j++)
            printf("%d ",comp[i][j]);
    return 0;
}