#include <bits/stdc++.h>

#define pb push_back
#define mp make_pair
#define MAXN 100001
#define DIM 8192

using namespace std;

class Reader
{
public:
    Reader(const char* filename)
    {
        if(filename[0]=='.'||filename[0]==0)
        {
            cout<<"Check INFILE.\n";
            return;
        }
        try
        {
            f.open(filename);
            pos = 0;
            if(f.fail())throw 1;
            f.read(buffer,DIM);
        }
        catch(int e)
        {
            cout<<"No INFILE.\n";
            delete this;
        }
    }
    inline Reader& operator >>(int& x)
    {
        x=0;
        sgn=1;
        while((buffer[pos]<'0'||buffer[pos]>'9')&&buffer[pos]!='-')
            if(++pos==DIM)
                f.read(buffer,DIM),pos=0;
        if(buffer[pos]=='-')sgn=-1,pos++;
        while(buffer[pos]>='0'&&buffer[pos]<='9')
        {
            x=x*10+buffer[pos]-'0';
            if(++pos==DIM)f.read(buffer,DIM),pos=0;
        }
        x*=sgn;
        return (*this);
    }
    inline Reader& operator >>(char* c)
    {
        aux = 0;
        while(isspace(buffer[pos]))
            if(++pos==DIM)
                f.read(buffer,DIM),pos=0;
        while(!isspace(buffer[pos]))
        {
            c[aux++]=buffer[pos];
            if(++pos==DIM)f.read(buffer,DIM),pos=0;
        }
        return (*this);
    }
    ~Reader()
    {
        f.close();
    }
private:
    ifstream f;
    int pos,aux,sgn;
    char buffer[DIM];
};

class Writer
{
public:
    Writer(const char* filename)
    {
        if(filename[0]=='.'||filename[0]==0)
            cout<<"Check OUTFILE. Nothing created.\n";
        else
        {
            g.open(filename);
            pos = 0;
        }
    }
    inline Writer& operator <<(int xx)
    {
        aux = 0;
        x = xx;
        if(xx<0)x=-x;
        if(x==0)
            nr[aux++]='0';
        while(x)
        {
            nr[aux++]=x%10+'0';
            x/=10;
        }
        if(xx<0)nr[aux++]='-';
        while(aux>0)
        {
            buffer[pos++]=nr[--aux];
            if(pos==DIM)g.write(buffer,DIM),pos=0;
        }
        return (*this);
    }
    inline Writer& operator <<(const char* c)
    {
        aux = 0;
        while(c[aux])
        {
            buffer[pos++]=c[aux++];
            if(pos==DIM)g.write(buffer,DIM),pos=0;
        }
        return (*this);
    }
    inline void flush()
    {
        g.write(buffer,pos);
        pos=0;
    }
    ~Writer()
    {
        g.write(buffer,pos);
        g.close();
    }
private:
    ofstream g;
    int pos,aux,x;
    char buffer[DIM],nr[21];
};

Reader f("biconex.in");
Writer g("biconex.out");

int n,m,t[MAXN],lv[MAXN],min_lv[MAXN],i,x,y,k;
vector<int> G[MAXN],sol[MAXN];
bitset<MAXN> use;
stack<int> s;

void df(int x)
{
    use[x]=1;
    lv[x]=lv[t[x]]+1;
    min_lv[x]=lv[x];
    s.push(x);
    for(auto it=G[x].begin();it!=G[x].end();it++)
        if(t[x]!=*it)
        {
            if(!use[*it])
            {
                t[*it]=x;
                s.push(x);
                df(*it);
                min_lv[x]=min(min_lv[x],min_lv[*it]);
                if(min_lv[*it]>=lv[x])
                {
                    k++;
                    while(s.top()!=x)
                    {
                        if(!sol[k].size()||s.top()!=sol[k].back())
                            sol[k].pb(s.top());
                        s.pop();
                    }
                    sol[k].pb(s.top());
                    s.pop();
                }
            }
            else
            {
                min_lv[x]=min(min_lv[x],lv[*it]);
            }
        }
}

int main()
{
    ios_base::sync_with_stdio(false);
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        G[x].pb(y);
        G[y].pb(x);
    }
    df(1);
    g<<k<<"\n";
    for(i=1;i<=k;i++,g<<"\n")
        for(auto it=sol[i].begin();it!=sol[i].end();it++)
            g<<(*it)<<" ";
    return 0;
}