/*#include <iostream>
#define NMAX 101

using namespace std;

int n, m, cnt, ct;
int A[NMAX][NMAX];
bool viz[NMAX];

void citire();
void rw();
void ctc(int ct);
void afisare();

int main()
{
    citire();
    rw();
    afisare();
}

void citire()
{
    int i, x, y;
    cin>>n>>m;
    for (i=1; i<=m; i++)
        {
         cin>>x>>y;
         A[x][y]=1;
        }
}

void ctc(int ct)
{
    int i;
    viz[ct]=1;
    for (i=1; i<=n; i++)
        if (A[ct][i] && A[i][ct] && !viz[i])
           ctc(i);
}

void rw()
{
    int i, j, k;
    for (k=1; k<=n; k++)
        for (i=1; i<=n; i++)
            if (A[i][k])
               for (j=1; j<=n; j++)
                if (A[k][j])
                   A[i][j]=1;
}

void afisare()
{
    int i, j;
    cnt=0;
    for (i=1; i<=n; i++)
         if (!viz[i])
            {
             cnt++;
             ctc(i);
            }
    cout<<cnt<<'\n';
}*/


/*#include <fstream>
#include <vector>
#define NMAX 100002

using namespace std;
ifstream fin ("ctc.in");
ofstream fout ("ctc.out");

int n, nr, poz;
vector<int> G[NMAX];
vector<int> GT[NMAX];
vector<int> ctc[NMAX];
int postordine[NMAX];
bool viz[NMAX];

void citire();
void DFS(int x);
void DFST(int x);
void afisare();

int main()
{
    int i;
    citire();
    ///parcurg DFS graful G retinand varfurile in postordine
    for (i=1; i<=n; i++)
        if (viz[i]==0)
           DFS(i);
    for (i=n; i>0; i--)
        if (viz[postordine[i]]==1)
           {
            nr++;
            DFST(postordine[i]);
           }
    afisare();
    return 0;
}

void citire()
{
    int i, x, y, m;
    fin>>n>>m;
    for (i=0; i<m; i++)
        {
         fin>>x>>y;
         G[x].push_back(y);
         GT[y].push_back(x);
        }
}

void DFS(int x)
{
   int i;
   viz[x]=1;
   for (i=0; i<G[x].size(); i++)
       if (viz[G[x][i]]==0)
          DFS(G[x][i]);
   postordine[++poz]=x;
}

void DFST(int x)
{
   int i;
   viz[x]=0;
   ctc[nr].push_back(x);
   for (i=0; i<GT[x].size(); i++)
       if (viz[GT[x][i]]==1)
          DFST(GT[x][i]);
}

void afisare()
{
    int i, j;
    fout<<nr<<'\n';
    for (i=1; i<=nr; i++)
        {
         for (j=0; j<ctc[i].size(); j++)
             fout<<ctc[i][j]<<' ';
         fout<<'\n';
        }
}*/


#include <fstream>
#include <vector>
#define NMAX 100002
using namespace std;
ifstream fin("ctc.in");
ofstream fout("ctc.out");

int n, poz;
///graful G repr. prin liste de adiacenta
vector<int>G[NMAX];
///graful transpus GT repr. prin liste de adiacenta
vector<int>GT[NMAX];
bool viz[NMAX];
int nr; ///nr de componente tare-conexe
vector<int>ctc[NMAX];
int postordine[NMAX];

void citire();
void DFS(int x);
void DFST(int x);
void afisare();

int main()
{
    int i;
    citire();
    ///parcurg DFS graful G retinand vf in postordine
    for (i=1; i<=n; i++)
        if (viz[i]==0)
            DFS(i);
    ///parcurg vectorul postordine de la dreaptra la stanga si DFS in GT
    for (i=n; i>0; i--)
        if (viz[postordine[i]]==1) ///aceste vf este nevizitat in GT
        {
            nr++;
            DFST(postordine[i]);
        }
    afisare();
    return 0;
}

void citire()
{
    int i, x, y, m;
    fin>>n>>m;
    for (i=0; i<m; i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        GT[y].push_back(x);
    }
}

void DFS(int x)
{
    int i;
    viz[x]=1;
    ///parcurg lista de adiacenta a lui x
    for (i=0; i<G[x].size(); i++)
        if (viz[G[x][i]]==0)
            DFS(G[x][i]);
    postordine[++poz]=x;
}

void DFST(int x)
{
    int i;
    viz[x]=0;
    ///retin acest vf in componenta conexa curenta
    ctc[nr].push_back(x);
    ///parcurg lista de adiacenta a lui x
    for (i=0; i<GT[x].size(); i++)
        if (viz[GT[x][i]]==1)
            DFST(GT[x][i]);
}

void afisare()
{
    int i, j;
    fout<<nr<<'\n';
    for (i=1; i<=nr; i++)
    {
        for (j=0; j<ctc[i].size(); j++)
            fout<<ctc[i][j]<<' ';
        fout<<'\n';
    }
}