#include <cstdio>
#include <vector>

using namespace std;

struct pereche
{
    int x,y;
};
vector<pereche> q;
vector<vector<int> > sol;
int vaz[100010],nivel[100010],nivmin[100010];
vector<int> v[100010];

vector<int> biconex(int x,int y)
{
    int a,b;
    vector<int> rez;
    do
    {
        a=q.back().x;
        b=q.back().y;
        q.pop_back();
        rez.push_back(b);
    }while(x!=a && y!=b);
    rez.push_back(a);
    return rez;
}

void dfs(int nod,int niv)
{
    nivel[nod]=nivmin[nod]=niv;
    vaz[nod]=1;
    for(int i=0;i<v[nod].size();i++)
        if(vaz[v[nod][i]]==0)
        {
            q.push_back({nod,v[nod][i]});
            dfs(v[nod][i],niv+1);
            nivmin[nod]=min(nivmin[nod],nivmin[v[nod][i]]);
            if(nivmin[v[nod][i]]>=nivel[nod]) sol.push_back(biconex(nod,v[nod][i]));
        }
        else nivmin[nod]=min(nivmin[nod],nivel[v[nod][i]]);
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    int n,m,x,y;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
        if(vaz[i]==0) dfs(i,1);
    printf("%d\n",sol.size());
    for(int i=0;i<sol.size();i++)
    {
        for(int j=0;j<sol[i].size();j++)
            printf("%d ",sol[i][j]);
        printf("\n");
    }
    return 0;
}