#include<iostream>
#include<algorithm>
#include<vector>
#include<list> 
using namespace std;
static const int MAX = 100000;

vector<int> G[MAX];
list<int> out;
bool V[MAX];
int N;

void dfs(int u) {
    V[u] = true;
    for(int i = 0; i < G[u].size(); i++) {
    	int v = G[u][i];
    	if(!V[v]) dfs(v);
    }
    out.push_front(u);
}


int main() {
	int s, t, M;
	
	cin >> N >> M;
	
	for(int i = 0; i < N; i++) V[i] = false;

    for(int i = 0; i < M; i++) {
    	cin >> s >> t;
    	G[s].push_back(t);
    }
    
    for(int i = 0; i < N; i++) {
    	if(!V[i]) dfs(i);
    }
    
    for(list<int> ::iterator it = out.begin(); it != out.end(); it++) {
    	cout << *it << endl;
    }
    
    return 0;
} 