#include<cstdio>
#include<vector>
#include<algorithm>
#include<stack>
using namespace std;
FILE*in=fopen("biconex.in","r");
FILE*out=fopen("biconex.out","w");
int n,m,i,j,a,b,ct;
vector<int> v[100005],ras[100005];
int viz[100005];
int poz[100005],low[100005];
stack<int> s;
void f(int nod,int dad)
{
    s.push(nod);
    low[nod]=nod;
    viz[nod]=1;
    for(int t=0;t<v[nod].size();t++)
    {
        int fiu=v[nod][t];
        if(fiu==dad)
        {
            continue;
        }
        if(viz[fiu]==0)
        {
            poz[fiu]=poz[nod]+1;
            f(fiu,nod);
            if(poz[low[fiu]]<poz[low[nod]])
            {
                low[nod]=low[fiu];
            }
            if(poz[nod]<=poz[low[fiu]])
            {
                while(s.top()!=fiu)
                {
                    ras[ct].push_back(s.top());
                    s.pop();
                }
                ras[ct].push_back(fiu);
                s.pop();
                ras[ct].push_back(nod);
                ct++;
            }
        }
        else if(viz[fiu]==1)
        {
            if(poz[fiu]<poz[low[nod]])
            {
                low[nod]=fiu;
            }
        }
    }
    viz[nod]=2;
}
int main()
{
    fscanf(in,"%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        fscanf(in,"%d%d",&a,&b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    poz[1]=1;
    f(1,0);
    fprintf(out,"%d\n",ct);
    for(i=0;i<ct;i++)
    {
        for(int t=0;t<ras[i].size();t++)
        {
            fprintf(out,"%d ",ras[i][t]);
        }
        fprintf(out,"\n");
    }
}