**Time limit:**1.00 s**Memory limit:**512 MB

You want to complete course $1$ as soon as possible. If there are several ways to do this, you want then to complete course $2$ as soon as possible, and so on.

Your task is to determine the order in which you complete the courses.

**Input**

The first input line has two integers $n$ and $m$: the number of courses and requirements. The courses are numbered $1,2,\dots,n$.

Then, there are $m$ lines describing the requirements. Each line has two integers $a$ and $b$: course $a$ has to be completed before course $b$.

You can assume that there is at least one valid schedule.

**Output**

Print one line having $n$ integers: the order in which you complete the courses.

**Constraints**

- $1 \le n \le 10^5$

- $1 \le m \le 2 \cdot 10^5$

- $1 \le a,b \le n$

**Example**

Input:

`4 2`

2 1

2 3

Output:

`2 1 3 4`