#include <bits/stdc++.h>
#define MAXN 1000006
#define EVER 36501
using namespace std;
int n,m,a,b;
vector <bool> Pross(MAXN, false);
vector <int> Ans(MAXN, 0);
void DFS (int v, vector <vector <int> > &G, vector <bool> &V, vector <bool> &C)
{
    V[v] = true;
    Pross[v] = true;
    for (auto nei:G[v])
    {
        if (V[nei] == false) DFS(nei, G, V, C);
        else if (Pross[nei]) C[v] = true;
    }
    Pross[v] = false;
}

void DFS2 (int v, vector <vector <int> > &G, vector <bool> &V)
{
    V[v] = true;
    Ans[v] = EVER;
    for (auto nei:G[v])
    {
        if (V[nei] == false) DFS2(nei, G, V);
    }
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> n >> m;
    n++;
    vector <vector <int> > Trans(n);
    vector <bool> vis(n, false);
    vector <bool> onCycle(n, false);
    vector <int> DegIn(n, 0);

    while (m--)
    {
        cin >> a >> b;
        a--, --b;
        Trans[b].push_back(a);
        DegIn[a]++;
    }
    DFS(n-1, Trans, vis, onCycle);
    for (int i=0; i!=n; ++i) if (vis[i] == false) Ans[i] = -1;
    for (int i=0; i!=n; ++i) vis[i] = false;

    for (int i=0; i!=n; ++i) if (onCycle[i] && vis[i] == false) DFS2(i, Trans, vis);
    for (int i=0; i!=n; ++i) vis[i] = false;
    for (int i=0; i!=n; ++i) if (Ans[i] != 0)
        {
            for (auto nei:Trans[i]) DegIn[nei]--;
            vis[i] = true;
        }

    queue <int> Q;
    for (int i=0; i!=n; ++i) if (DegIn[i] == 0 && Ans[i] == 0) Q.push(i);
    Ans[n-1] = 1;

    while (Q.empty() == false)
    {
        int node = Q.front();
        Q.pop();

        for (auto nei:Trans[node])
        {
            Ans[nei] = min(EVER, Ans[nei] + Ans[node]);
            DegIn[nei]--;
            if (DegIn[nei] == 0) Q.push(nei);
        }
    }

    int maxVal = -1;
    for (auto v:Ans) maxVal = max(maxVal, v);
    for (int i=0; i!=n; ++i) if (Ans[i] == maxVal) Q.push(i+1);
    if (maxVal == EVER) cout << "zawsze";
    else cout << maxVal;
    cout << "\n" << Q.size() << "\n";
    while (Q.empty() == false)
    {
        cout << Q.front() << " ";
        Q.pop();
    }
    return 0;
}