#include <iostream>
#include <fstream>
#include <bitset>
#include <vector>

#define NMAX 8193

using namespace std;

ifstream fin ("felinare.in");
ofstream fout ("felinare.out");

int n, m, muchie[NMAX][NMAX], l[NMAX], r[NMAX];
vector<int> G[NMAX], GT[NMAX];
bitset<NMAX> viz;

void citire()
{
    fin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int x, y;
        fin >> x >> y;
        G[x].push_back(y);
        GT[y].push_back(x);
    }
}

int match(int nod)
{
    if (viz[nod] == true)
        return false;
    viz[nod] = true;

    for (auto it:G[nod])
    {
        cout << it << " ";
        if (muchie[nod][it] == 0)
        {
            l[nod] = 0;
            r[it] = 1;
            muchie[nod][it] = 1;
            return true;
        }
        if (muchie[nod][it] == 1)
        {
            if (l[nod] == 0 && match(it))
            {
                l[nod] = 1;
                r[it] = 0;
                muchie[nod][it] = 1;
                return true;
            }
        }
    }
    return false;
}

int main()
{
    citire();

    bool ok = true;
    while (ok)
    {
        ok = false;
        viz.reset();

        for (int i = 1; i <= n; i++)
            if (!viz[i])
                ok |= match(i);
    }

    for (int i = 1; i <= n; i++)
    {
        if (G[i].size() == 0) l[i] = 1;
        if (GT[i].size() == 0) r[i] = 1;
    }

    int sol = 0;
    for (int i = 1; i <= n; i++)
    {
        // fout << l[i] << " " << r[i] << "\n";
        sol += (l[i] + r[i]);
    }

    fout << sol << "\n";
    for (int i = 1; i <= n; i++)
    {
        if (l[i] == 0 && r[i] == 0) fout << "0\n";
        if (l[i] == 1 && r[i] == 0) fout << "1\n";
        if (l[i] == 0 && r[i] == 1) fout << "2\n";
        if (l[i] == 1 && r[i] == 1) fout << "3\n";
    }
    return 0;
}