#include <bits/stdc++.h>
using namespace std;
int n, m;
vector<int> e[5005];
int d[5005];
queue<int> q;
vector<int> ans;
int main()
{
    cin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int u, v;
        cin >> u >> v;
        e[u].push_back(v);
        d[v]++;
    }
    for (int i = 1; i <= n; i++)
        if (d[i] == 0)
            q.push(i);
    bool flag = false; // 多解标记
    while (!q.empty())
    {
        if (q.size() > 1)
            flag = true;
        int now = q.front();
        q.pop();
        ans.push_back(now);
        for (int i = 0; i < e[now].size(); i++)
        {
            int v = e[now][i];
            d[v]--;
            if (d[v] == 0)
                q.push(v);
        }
    }
    for (int i = 0; i < ans.size(); i++)
        cout << ans[i] << "\n";
    cout << flag;
    return 0;
}