// UUID: afeb05b0-036d-4696-849d-ecb540c84701
#include <bits/stdc++.h>
#include <queue>
using namespace std;

#define int long long
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;cin >> n >> m;
    vector<vector<int>> g(n+1, vector<int>(n+1));
    vector<int> c(n+1, 0);
    vector<int> output;
    for(int i = 0; i < m; i++)
    {
        int a,b;cin >> a >> b;
        c[b]++;
        g[a].push_back(b);
    }
    int global_idx = -1;
    queue<int> q;
    for(int i = 1; i <= n; i++)
    {
        if(c[i] == 0) q.push(i); 
    }

    if(q.empty())
    {
        cout << "0";
        return 0;
    } 
    if(q.size() > 1) global_idx = 0;

    while(!q.empty())
    {
        int v = q.front();
        output.push_back(v);
        q.pop();
        int count = 0;
        int idx = -1;
        for(int e: g[v])
        {
            c[e]--;
            if(c[e] == 0)
            {
                count++;
                idx = output.size();
                q.push(e);
            } 
        }
        if(count == 0 && q.empty() && output.size() < n)
        {
            cout << "0";
            return 0;
        }
        else if(count > 1)
        {
            global_idx = idx;
        }
    }
    if(global_idx == -1) 
    {
        cout << "1\n";
        for(int a: output) cout << a << " ";
    }
    else
    {
        cout << "2\n";
        for(int a: output) cout << a << " ";
        swap(output[global_idx], output[global_idx+1]);
        cout << "\n";
        for(int a: output) cout << a << " ";    
    } 
}