#include <iostream>
#include <vector>
#include <unordered_set>
#include <queue>
#include <fstream>

using namespace std;

int main() {
    int i, x, y, n, m;

    ifstream f("sortaret.in");
    ofstream g("sortaret.out");
    f >> n >> m;

    vector<vector<int>> adj(n + 1);
    vector<int> in_edges(n + 1, 0);
    vector<int> topo;
    queue<int> q;


    for (i = 1; i <= m; ++i) {
        f >> x >> y;
        adj[x].push_back(y);
        in_edges[y]++;
    }

    for (i = 1; i <= n; ++i) {
        if (in_edges[i] == 0) {
            q.push(i);
        }
    }

    while (!q.empty()) {
        int node = q.front();
        q.pop();
        topo.push_back(node);

        for (auto neighbor = adj[node].begin(); neighbor != adj[node].end(); ++neighbor) {
            --in_edges[*neighbor];

            if (in_edges[*neighbor] == 0) {
                q.push(*neighbor);
            }
        }
    }

    bool hasEdges = false;
    for (i = 1; i <= n; ++i) {
        if (in_edges[i]) {
            hasEdges = true;
            break;
        }
    }

    if (hasEdges) {
        g << "Cycle found";
    } else {
        for (int node : topo) {
            g << node << ' ';
        }
    }

    f.close();
    g.close();

    return 0;
}