#include <bits/stdc++.h>

using namespace std;

int n,m,niv[100005],low[100005],nrcom;
vector <int > g[100005];
vector <int > punct,r;
stack<int> st;
vector <vector <int >  > sol;
void citire()
{
    scanf("%d%d",&n,&m);
    for (int i=1;i<=m;++i)
    {
        int nod1,nod2;
        scanf("%d%d",&nod1,&nod2);
        g[nod1].push_back(nod2);
        g[nod2].push_back(nod1);
    }
}
void fac_sol(int nod,int tata)
{
    r.clear();
    while(tata!=st.top())
        {
            r.push_back(st.top());
            st.pop();
        }
    r.push_back(tata);
    sol.push_back(r);
}
void alg(int nod,int tata)
{
    niv[nod]=low[nod]=niv[tata]+1;
    for (vector <int > :: iterator it=g[nod].begin();it!=g[nod].end();++it)
    {
        if (*it==tata)
            continue;
        if (!niv[*it])
        {
            st.push(*it);
            alg(*it,nod);
            if (low[*it]<low[nod])
                low[nod]=low[*it];
            if (low[*it]>=niv[nod])
                fac_sol(*it,nod);
        }
        else
            if (niv[*it]<low[nod])
                low[nod]=niv[*it];
    }
}
void afish(){
    printf("%d\n", sol.size());
    for(int i = 0; i < sol.size(); ++i){
        for(int j = 0; j < sol[i].size(); ++j)
            printf("%d ", sol[i][j]);
        printf("\n");
    }
}
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    citire();
    for (int i=1;i<=n;++i)
        if (!niv[i])
            {
                st.push(i);
                alg(i,0);
                st.pop();
            }
    afish();
    return 0;
}