#include <fstream>
#include <vector>
#define N 100005

using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");

int n,m,level=1, nr_biconex, t;
int lv[N], low[N], parent[N], stck[N];
vector<int> v[N], afis[N];

void dfs(int start){
    lv[start] = low[start] = level;
    stck[t] = start;
    t++;

    for(int i=0; i<v[start].size(); i++){
        int neig = v[start][i];
        if(lv[neig] == 0){
            level++;
            parent[neig] = start;
            dfs(neig);

            low[start] = min(low[start], low[neig]);

            if(low[neig] >= lv[start]){
                t--;
                while(stck[t] != start){
                    afis[nr_biconex].push_back(stck[t]);
                    t--;
                }
                afis[nr_biconex].push_back(start);
                t++;
                nr_biconex++;
            }
        }
        else{
            if(parent[neig] != start)
                low[start] = min(low[start], lv[neig]);
        }
    }
}
int main()
{
    f>>n>>m;
    int x,y;
    for(int i=0; i<m; i++){
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    dfs(1);

    g<<nr_biconex<<'\n';
    for(int i=0; i<nr_biconex; i++){
        for(int j=0; j<afis[i].size(); j++)
            g<<afis[i][j]<<' ';
        g<<'\n';
    }

    return 0;
}