Topological sort P14952

We must perform n tasks, one at a time. Furthermore, some tasks must be done before others: there are m precedence relations between tasks. Write a program to print a way to sort the n tasks satisfying the m given precedences.

Input

Input consists of several cases. Every case begins with n, followed by m, followed by m ‍distinct pairs x y that indicate that task x must be done before task y. You can assume 1 ≤ n ≤ 10⁴, 0 ≤ m ≤ 10n, and that the tasks are numbered from 0 to n − 1.

Output

For every case, print the lexicographically smallest order of the n tasks that fulfills the m ‍given precedences. There will always be, at least, one solution.