#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

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


const int MAX=1e5;
int n,i,m,node1,node2,j,k,nr;
bool d[1005][1005],viz[MAX+5];
vector <int> edge[MAX+5],compconex[MAX+5];

void dfs(int node)
{
    viz[node]=1;
    compconex[nr].push_back(node);

    for (auto x: edge[node])
        if (!viz[x] && d[x][node])
            dfs(x);
}

int main()
{
    ios_base::sync_with_stdio(false);
    fin.tie(0); fout.tie(0);

    fin>>n>>m;

    while (m--)
    {
        fin>>node1>>node2;
        cout<<node1<<" "<<node2<<endl;
        d[node1][node2]=1;
        edge[node1].push_back(node2);
    }

    for (k=1; k<=n; k++)
    {
        for (i=1; i<=n; i++)
        {
            for (j=1; j<=n; j++)
            {
                if (d[i][k] && d[k][j])
                    d[i][j]=1;
            }
        }
    }

    for (i=1; i<=n; i++)
    {
        if (!viz[i])
        {
            nr++;
            dfs(i);
        }
    }

    fout<<nr<<'\n';

    for (i=1; i<=nr; i++)
    {
        sort(compconex[i].begin(),compconex[i].end());
        for (auto x: compconex[i])
            fout<<x<<" ";
        fout<<'\n';
    }


    return 0;
}