#include<bits/stdc++.h>
using namespace std;

const int maxN=(1e5)+5;

int biconexe,st[maxN],vf;
int low[maxN],lvl[maxN];
bool seen[maxN];
vector<int> C[maxN],v[maxN];
void dfs(int nod,int fat,int niv)
{
    st[++vf]=nod;
    low[nod]=niv;
    lvl[nod]=niv;
    seen[nod]=1;

    for(auto it:v[nod])
    {
        if(it==fat) continue;
        if(seen[it]) //poate ajunge la un stramos
        {
            low[nod]=min(low[nod],lvl[it]);
            continue;
        }

        dfs(it,nod,niv+1);

        low[nod]=min(low[nod],low[it]);

        if(low[it]>=lvl[nod])
        {
            biconexe++;
            int x=0;
            do
            {
                x=st[vf];
                vf--;
                C[biconexe].push_back(x);
            }while(x!=it);
            C[biconexe].push_back(nod);
        }
    }
}

int n,m,x,y;

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);

    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }

    dfs(1,0,1);

    printf("%d\n",biconexe);

    for(int i=1;i<=biconexe;i++)
    {
        for(auto it:C[i])
            printf("%d ",it);

        printf("\n");
    }
    return 0;
}