Sticks

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import java.util.stream.Collectors;

public class Sticks {

    public static void main(String[] args) throws IOException {
        BufferedReader buffReader = new BufferedReader(new InputStreamReader(System.in));

        int sticks = Integer.parseInt(buffReader.readLine());
        int stickPlacings = Integer.parseInt(buffReader.readLine());

        HashMap<Integer, Stick> allSticks = new HashMap<>();

        for (int i = 0; i < sticks; i++) {
            allSticks.put(i, new Stick(i));
        }

        //place sticks
        for (int i = 0; i < stickPlacings; i++) {
            int[] values = Arrays.stream(buffReader.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
            int onTop = values[0];
            int below = values[1];
            Stick stickOnTop = allSticks.get(onTop);
            Stick stickBelow = allSticks.get(below);
            allSticks.get(below).addOnTop(stickOnTop);
            allSticks.get(onTop).addBelow(stickBelow);
        }

        for (int i = 0; i < sticks; i++) {
            Collections.sort(allSticks.get(i).below, (o1, o2) -> Integer.compare(o2.getValue(), o1.getValue()));
        }
        //lift
        Queue<Stick> stickQueue = new LinkedList<>();

        for (int i = sticks - 1; i > 0; i--) {
            Stick current = allSticks.get(i);
            if (current.onTop.size() == 0) {
                stickQueue.add(current);
            }
        }

        HashSet<Integer> results = new LinkedHashSet<>();
        boolean[] canBeLifted = new boolean[sticks];

        while (!stickQueue.isEmpty()) {
            Stick current = stickQueue.poll();

            if (current.onTop.size() == 0) {
                canBeLifted[current.getValue()] = true;
                results.add(current.getValue());
            }

            for (Stick stick : current.below) {
                if (canBeLifted[current.getValue()]) {
                    stick.onTop.remove(current);
                    if (stickQueue.peek()== null || stickQueue.peek().getValue() != stick.getValue()) {
                        stickQueue.add(stick);
                    }
                }
            }
        }
        if (results.size() != sticks) {
            System.out.println("Cannot lift all sticks");
        }
        System.out.println(String.join(" ", results.stream().map(String::valueOf).collect(Collectors.toList())));
    }

    private static class Stick {

        private int value;
        private List<Stick> onTop;
        private List<Stick> below;

        private Stick(int value) {
            this.value = value;
            this.onTop = new LinkedList<>();
            this.below = new LinkedList<>();
        }

        public void addBelow(Stick stick) {
            this.below.add(stick);
        }

        public void addOnTop(Stick stick) {
            this.onTop.add(stick);
        }

        public int getValue() {
            return this.value;
        }
    }
}