#include <bits/stdc++.h>
#define DIM 2000001

using namespace std;

ifstream fin("biconex.in");

ofstream fout("biconex.out");

stack <int> stk;

vector <int> G[DIM];

vector <int> ret[DIM];

int found[DIM], low[DIM], lvl[DIM];

int t, n, i, m, x, y, bcc;

void dfs(int node, int dad){

    found[node] = 1;

    low[node] = lvl[node] = ++t;

    stk.push(node);

    for(auto k : G[node]){

        if(k == dad)

            continue;

        if(found[k])

            low[node] = min(low[node], lvl[k]);

        else {

            dfs(k, node);

            low[node] = min(low[node], low[k]);

            if(lvl[node] <= low[k]){

                ++bcc;

                while(k != stk.top()){

                    ret[bcc].push_back(stk.top());

                    stk.pop();

                }

                ret[bcc].push_back(stk.top());

                stk.pop();

                ret[bcc].push_back(node);



            }

        }

    }

}

int main(){

    fin >> n >> m;

    while(m--){

        fin >> x >> y;

        G[x].push_back(y);

        G[y].push_back(x);

    }

    for(i=1;i<=n;i++)

        if(!found[i])

            dfs(i, 0);

    fout << bcc << "\n";

    for(i=1;i<=bcc;i++, fout << "\n")

        for(auto k : ret[i])

            fout << k << " ";

}