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**Task** | Statistics

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

You have to complete $n$ courses. There are $m$ requirements of the form "course $a$ has to be completed before course $b$". Your task is to find an order in which you can complete the courses.

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

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

Print an order in which you can complete the courses. You can print any valid order that includes all the courses.

If there are no solutions, print "IMPOSSIBLE".

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

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

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

Input:

`5 3`

1 2

3 1

4 5

Output:

`3 4 1 5 2`