#include<iostream>

#include<vector>

#include<queue>

using namespace std;

int num[];

int main()

{

    queue<int>q;

    queue<int>ans;

    int n,m;

    cin>>n>>m;

    int x,y;

    vector<int>u[];

    for(int i=;i<=m;i++){

        cin>>x>>y;

        u[x].push_back(y);

        num[y]++;

    }

    for(int i=;i<n;i++){

        if(num[i]==){q.push(i);}

    }

    while(!q.empty()){

        int k=q.front();q.pop();ans.push(k);

        for(int i=;i<u[k].size();i++){

            num[u[k][i]]--;

            if(num[u[k][i]]==){q.push(u[k][i]);}

        }

    }

    while(!ans.empty()){

        cout<<ans.front()<<endl;

        ans.pop();

    }

}