#include <bits/stdc++.h>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
const int NMAX=1e5+4;

int n,m,id,cntCb;
int dfn[NMAX],low[NMAX];
stack <int> stk;
vector <int> g[NMAX];
vector <int> cb[NMAX];

void dfs(int node, int father){
    dfn[node]=++id;
    low[node]=dfn[node];
    for(auto it:g[node]){
        if(it!=father){
            if(low[it])
                low[node]=min(low[node], low[it]);
            if(!dfn[it]){
                dfs(it, node);
                low[node]=min(low[node], low[it]);
                if(low[it]>=dfn[node]){
                    //am gasit o componenta biconexa =)
                    while(!stk.empty()){
                        cb[cntCb].push_back(stk.top());
                        stk.pop();
                    }
                    cb[cntCb].push_back(node);
                    ++cntCb;
                }
            }
        }
    }
    stk.push(node);
}

int main(){
    int x,y;
    fin>>n>>m;
    for(int i=0;i<m;++i){
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1,0);
    fout<<cntCb<<'\n';
    for(int i=0;i<cntCb;++i){
        for(auto it:cb[i])
            fout<<it<<' ';
        fout<<'\n';
    }
    return 0;
}