Problem: <image>


A directed acyclic graph (DAG) can be used to represent the ordering of tasks. Tasks are represented by vertices and constraints where one task can begin before another, are represented by edges. For example, in the above example, you can undertake task B after both task A and task B are finished. You can obtain the proper sequence of all the tasks by a topological sort.

Given a DAG $G$, print the order of vertices after the topological sort.

Constraints

* $1 \leq |V| \leq 10,000$
* $0 \leq |E| \leq 100,000$
* There are no parallel edges in $G$
* There are no self loops in $G$

Input

A directed graph $G$ is given in the following format:
$|V|\;|E|$
$s_0 \; t_0$
$s_1 \; t_1$
:
$s_{|E|-1} \; t_{|E|-1}$



$|V|$ is the number of vertices and $|E|$ is the number of edges in the graph. The graph vertices are named with the numbers $0, 1,..., |V|-1$ respectively.

$s_i$ and $t_i$ represent source and target nodes of $i$-th edge (directed).

Output

Print the vertices numbers in order. Print a number in a line.

If there are multiple possible solutions, print any one of them (the solution is judged by a special validator).

Example

Input

6 6
0 1
1 2
3 1
3 4
4 5
5 2


Output

0
3
1
4
5
2

Solution (in JAVA):

Solution:
import java.util.Iterator;
import java.util.LinkedList;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;


class GraphTopological2 {
	private int totalVertex;
	private int totalEdge;
	private int [] indegree;
	private Set<Integer> s = new HashSet<Integer>();
	private LinkedList<LinkedList<Integer>> adjList;
	public GraphTopological2() {
		totalVertex = 0; 
	}
	public void loadAdjList() {
		Scanner in = new Scanner(System.in);
		totalVertex = in.nextInt();
		totalEdge = in.nextInt();
		adjList = new LinkedList<LinkedList<Integer>>();
		indegree = new int[totalVertex];
		for(int i=0; i<totalVertex; i++){
			LinkedList<Integer> tmp = new LinkedList<Integer>();
			adjList.add(tmp);
			s.add(i);
		}
		for(int i = 0; i < totalEdge; i++) {
			int v = in.nextInt();
			int neighbor = in.nextInt();
			adjList.get(v).add(neighbor); // add its neighbor to its list
			indegree[neighbor]++; // increase its indegree by 1	
		}
		in.close();
	}
	
	public void Topological(){
		while(!s.isEmpty()){
			Iterator<Integer> itr = s.iterator();
			while (itr.hasNext()) {
				int k = itr.next();
				if(indegree[k]==0){
					System.out.println(k);
					Iterator<Integer> it = adjList.get(k).iterator();
					while (it.hasNext()) {
				    	int neib = it.next();// get all neighbors of the current node that has no incoming edges
				    	indegree[neib]--;					    	
				   }
		    	   s.remove(k);
		    	   break;
				}
			}
		}
	}

}

public class Main {
	public static void main(String argv[]) {
		GraphTopological2 g = new GraphTopological2();
		g.loadAdjList();
		g.Topological();
	}
}