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**Task** | Statistics

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

You want to complete $n$ courses that have requirements of the form "course $a$ has to be completed before course $b$".

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.

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.

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

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

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

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

Input:

`4 2`

2 1

2 3

Output:

`2 1 3 4`