A. Ascending mountains
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Isa, wanting to join the climbing group Climbing Camels, decided to start climbing mountains. In order to be accepted as a climbing camel, Isa must climb all the available $$$N$$$ mountains. However, for Isa to be allowed to climb the mountain of a certain level, she must have climbed other easier mountains first.

Your mission is: given the number of mountains and pairs of mountains $$$(A, B)$$$ where mountain of level $$$A$$$ must be climbed before mountain of level $$$B$$$ determine the lexicographically smallest order in which Isa can climb all the mountains and become a climbing camel.

An order $$$A$$$ is lexicographically smaller than another order $$$B$$$ if there exists an $$$i$$$ such that $$$A_i \lt B_i$$$ and for all $$$j$$$ with $$$1 \leq j \lt i$$$, $$$A_j = B_j$$$.

Input

The first line contains two integers $$$N$$$ and $$$M$$$ $$$(1 \leq N, M \leq 2 \cdot 10^5)$$$.

In each of the next $$$M$$$ lines, two integers $$$A$$$ and $$$B$$$ $$$(1 \leq A \lt B \leq N)$$$ are given, where in order to climb the mountain of level $$$B$$$, Isa must first have climbed the mountain of level $$$A$$$. Certainly $$$A \lt B$$$, because a lower difficulty level is easier to climb .

Output

Print $$$N$$$ numbers representing the lexicographically smallest order that Isa must follow to become a climbing camel, or $$$-1$$$ if there is no existing order that allows Isa to climb all the mountains.

Examples
Input
3 2
1 2
2 3
Output
1 2 3
Input
5 1
1 5
Output
1 2 3 4 5