#include <iostream>
#include <vector>
#include <queue>

using namespace std;

int main(){
    int n, m;
    cin >> n >> m;
    vector<vector<int>> adj(n);
    vector<int> degree(n, 0);

    for(int i = 0; i < m; i++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        degree[v]++;
    }

    priority_queue<int, vector<int>, greater<int>> pq;

    for(int i = 0; i < n; i++){
        if(degree[i] == 0){
            pq.push(i);
        }
    }
    vector<int> ans;

    while(!pq.empty()){
        int u = pq.top();
        pq.pop();
        ans.push_back(u);
        for(int v : adj[u]){
            degree[v]--;
            if(degree[v] == 0){
                pq.push(v);
            }
        }
    }

    if(ans.size() != n){
        cout << "unworkable project" << endl;
    }else{
        for(int i = 0; i < n; i++){
            cout << ans[i] << " ";
        }
        cout << endl;
    }

    return 0;
}