#include <bits/stdc++.h>

using namespace std;

#define f first
#define s second
#define mp make_pair

stack<pair<int,int> >s;
vector<int>v[100010],c[100010];
int viz[100010],niv[100010],low[100010],t[100010],b[100010];
int n,m,total;

void df(int i){
    int k,j,nr=v[i].size(),fiu;
    pair<int,int> a;
    viz[i]=1;low[i]=niv[i];
    for (j=0;j<nr;j++){
        fiu=v[i][j];
        if (fiu!=t[i]&&niv[i]>niv[fiu]) s.push(mp(i,fiu));
        if (!viz[fiu]){
            t[fiu]=i;
            niv[fiu]=niv[i]+1;
            df(fiu);
            low[i]=min(low[i],low[fiu]);
            if (low[fiu]>=niv[i]){
                a=s.top();total++;
                s.pop();
                b[a.f]=1;
                b[a.s]=1;
                while ((a.f!=i||a.s!=fiu)&&(a.f!=fiu||a.s!=i)){
                    a=s.top();
                    s.pop();
                    b[a.f]=1;
                    b[a.s]=1;
                }
                for (k=1;k<=n;k++) if (b[k]) {c[total].push_back(k);b[k]=0;}
            }
        }
        else if (fiu!=t[i]){
            low[i]=min(low[i],niv[fiu]);
        }
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    int i,x,y,r,rr,j;
    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);
    }

    niv[1]=1;
    r=1;
    df(1);
    printf("%d\n",total);
    for (i=1;i<=total;i++){
        rr=c[i].size();
        for (j=0;j<rr;j++)
            printf("%d ",c[i][j]);
        printf("\n");
    }
    return 0;
}