#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>
#define DIM 100010
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n, m, i, j, v[DIM], l[DIM], k, x, y, b, u;

vector<int> L[DIM], B[DIM];
stack< pair<int, int> > st;
pair<int, int> aux;

inline int minim(int x, int y){
    return (x<y?x:y);
}

void dfs(int x, int niv, int t){
    v[x]=1;
    l[x]=niv;
    for(int i=0; i<L[x].size(); i++)
    {
        int y=L[x][i];
        if(v[y]==0)
        {
            st.push( make_pair(x, y) );
            dfs(y, niv+1, x);
            if(l[y]>=niv)
            {
                b++;
                do
                {
                    aux=st.top();
                    st.pop();
                    B[b].push_back(aux.first);
                    B[b].push_back(aux.second);
                }while(aux.first!=x || aux.second!=y);
            }
        }
        if(y!=t)
            l[x]=minim(l[x], l[y]);
    }
}

int main(){
    f>>n>>m;
    for(i=1; i<=m; i++)
    {
        f>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1, 1, 0);
    g<<b<<"\n";
    for(i=1; i<=b; i++)
    {
        sort(B[i].begin(), B[i].end());
        g<<B[i][0]<<' ';
        for(j=1; j<B[i].size(); j++)
            if(B[i][j]!=B[i][j-1])
                g<<B[i][j]<<' ';
        g<<"\n";
    }
    return 0;
}