import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
import java.util.ArrayList;
import java.util.Iterator;

class Graph {
	private int totalVertex;
	private int totalEdges;
	private LinkedList<LinkedList<Integer>> adjList;
	int[] discover;
	int[] finish;
	
	//adjacency list of edges
	public Graph() { 
			totalVertex = 0;
			totalEdges = 0;
		}
	public void loadAdjList() {
		Scanner in = new Scanner(System.in);
		totalVertex = in.nextInt();
		totalEdges = in.nextInt();
		adjList = new LinkedList<LinkedList<Integer>>();
		for(int i = 0; i < totalVertex; i++) {
			adjList.add(new LinkedList<Integer>());
		}
		//int previdx = -1;
		for(int i = 0; i < totalEdges; i++) {
			int idx1 = in.nextInt();
			int idx2 = in.nextInt();
			adjList.get(idx1).add(idx2);
		}
//		for(int i = 0; i < totalVertex; i ++) {
//			LinkedList<Integer> tmp = new LinkedList<Integer>();
//			int idx1 = in.nextInt() - 1;
//			int degree = in.nextInt();
//			//System.out.println("mark idx1 = " + idx1 + " degree = " + degree);
//			for(int j = 0; j < degree; j ++) {
//				int idx2 = in.nextInt() - 1;
//				tmp.add(idx2);
//			}	
//			adjList.add(tmp);
//		}
		in.close();
	}
	public void printAdjMatrix() {
		Integer[][] adjMatrix = new Integer[totalVertex][totalVertex];
		
		for(int i = 0; i < adjMatrix.length; i++) {
			for(int j = 0; j < totalVertex ; j++) {
				adjMatrix[i][j] = 0;
			}
		}
		
		int z = 0;
		//int j = 0;
		
		for(LinkedList<Integer> ll: this.adjList) {
			for(Integer ele : ll) {
				adjMatrix[z][ele] = 1;
			}
			z++;
		}
		
		for(int m = 0; m < adjMatrix.length; m++) {
			for(int n = 0; n < totalVertex; n++) {
				if(n == totalVertex - 1) {
					System.out.println(adjMatrix[m][n]);
				}
				else {
					System.out.print(adjMatrix[m][n] + " ");
				}
				//System.out.print(adjMatrix[m][n] + " ");
			}
		}
	}
	
	public int DFS(int v, int time) {
	    
//		if(discover[v] != -1) {
//			return time;
//		}
		
		discover[v] = time;
		for(Integer ele : this.adjList.get(v)) {
			if(discover[ele] == -1) {
				time += 1;
				time = DFS(ele, time);
			}
		}
			//finish[v] = time + 1;
		
		finish[v] = time + 1;
		return time + 1;
	}
	
	public void DFS(int v, ArrayList<Integer> arr) {
		discover[v] = 1;
		
		for(Integer ele: this.adjList.get(v)) {
			if(discover[ele] == -1) {
				DFS(ele, arr);
			}
		}
		arr.add(v);
	}
	
	public void BFS() {
		//int iter = 0;
		Queue<Integer> q = new LinkedList<>();
		q.add(0);
		int[] distances = new int[totalVertex];
		distances[0] = 0;
		for(int i = 1; i < distances.length; i++) {
			distances[i] = -1;
		}
		while(q.isEmpty() != true) {
			int u = q.remove();
			//System.out.println(u+1);
			//iter += 1;
			for(Integer ele : this.adjList.get(u)) {
				//System.out.println(u);
				if(distances[ele] == -1) {
					q.add(ele);
					distances[ele] = distances[u]+1;
				}
			}
		}
		
		for(int i = 0; i < distances.length; i++) {
			System.out.println(i + 1 + " " + distances[i]);
		}
	}
	
	public void searchGraph() {
		this.discover = new int[totalVertex];
		for(int i = 0; i < discover.length; i++) {
			discover[i] = -1;
		}
		this.finish = new int[totalVertex];
		
		int dis_time = 0;
		
		for(int i = 0; i < totalVertex; i++){
			if(discover[i] == -1) {
				dis_time = DFS(i, dis_time);
				dis_time += 1;
			}
		}
		
		for(int i = 0; i < totalVertex; i++) {
			System.out.println(i + 1 + " " + (discover[i] + 1) + " " + (finish[i] + 1));
		}
	}
	
	
	public void toposort() {
		ArrayList<Integer> arr = new ArrayList<Integer>();
		this.discover = new int[totalVertex];
		for(int i = 0; i < totalVertex; i++) {
			discover[i] = -1;
		}
		for(int i = 0; i < totalVertex; i++){
			if(discover[i] == -1) {
				DFS(i, arr);
			}
		}
		for(int i = arr.size() - 1; i >= 0; i--) {
			System.out.println(arr.get(i) + " ");
		}
		
	}
}


//change class name GraphRepresentation to Main() for submission to AIZU
class Main {
	public static void main(String argv[]) {
		Graph g = new Graph();
		g.loadAdjList();
		//g.BFS();
		//g.printAdjMatrix();
		//g.searchGraph();
		g.toposort();
		
	}
}


Measured memory_bytes: 73928