#include<fstream>
#include<vector>
#include<stack>
#define nx 100007
using namespace std;
int n,m,i,j,nr,k,x,y,niv[nx],low[nx],critic[nx];
vector<int>v[nx],sol[nx];
stack<int>q;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

void biconex(int x,int y)
{
    k++;
    sol[k].push_back(x);
    while(q.size() && q.top()!=y)
    {
        sol[k].push_back(q.top());
        q.pop();
    }
    sol[k].push_back(y);
    q.pop();
}


void df(int x)
{
    low[x]=niv[x];

    for(int j=0;j<v[x].size();j++)
    {
        int y=v[x][j];
        if(!niv[y])
        {
            niv[y]=niv[x]+1;
            if(y==i)nr++;
            q.push(y);

            df(y);

            low[x]=min(low[x],low[y]);
            if(low[y]>=niv[x])biconex(x,y);
        }
        low[x]=min(low[x],niv[y]);
    }
}

int main()
{
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    q.push(1);
    niv[1]=1;
    df(1);


    fout<<k<<'\n';
    for(i=1;i<=k;i++)
    {
        for(j=0;j<sol[i].size();j++)fout<<sol[i][j]<<' ';
        fout<<'\n';
    }

    return 0;
}