#include<cstdio>
#include<vector>
#include<stack>
#include<algorithm>

using namespace std;

const int nmax=1e5+5;

typedef pair<int,int> ii;

vector<int> adj[nmax],dfn,low;
vector< vector<int> > c;
stack<ii> stk;

inline int min(int a,int b)
{
    if(a>b)
        return b;
    return a;
}

inline void cache_bc(int x,int y)
{
    vector<int> con;
    int tx,ty;
    do
    {
        tx=stk.top().first;
        ty=stk.top().second;
        stk.pop();
        con.push_back(tx);
        con.push_back(ty);
    }while(tx!=x||ty!=y);
    c.push_back(con);
}

inline void df(int node,int fn,int number)
{
    vector<int>::iterator it;
    dfn[node]=low[node]=number;
    for(it=adj[node].begin();it!=adj[node].end();++it)
    {
        if(*it==fn)
            continue;
        if(dfn[*it]==-1)
        {
            stk.push(ii(node,*it));
            df(*it,node,number+1);
            low[node]=min(low[node],low[*it]);
            if(low[*it]>=dfn[node])
                cache_bc(node,*it);
        }
        else
            low[node]=min(low[node],dfn[*it]);
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    int x,i,j,y,n,m;
    scanf("%d%d",&n,&m);
    dfn.resize(n+1);
    low.resize(n+1);
    dfn.assign(n+1,-1);
    for(i=1;i<=m;++i)
    {
        scanf("%d%d",&x,&y);
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    df(1,0,0);
    printf("%d\n",c.size());
    for(i=0;i<c.size();++i)
    {
        sort(c[i].begin(),c[i].end());
        c[i].erase(unique(c[i].begin(),c[i].end()),c[i].end());
        for(j=0;j<c[i].size();++j)
            printf("%d ",c[i][j]);
        printf("\n");
    }

}