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**Task** | Statistics

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

There are $n$ cities and $m$ flight connections between them. A city is called a

Your task is to find all critical cities from Syrjälä to Lehmälä.

The first input line has two integers $n$ and $m$: the number of cities and flights. The cities are numbered $1,2,\dots,n$. City $1$ is Syrjälä, and city $n$ is Lehmälä.

Then, there are $m$ lines describing the roads. Each line has two integers $a$ and $b$: there is a flight from city $a$ to city $b$. All flights are one-way flights.

You may assume that there is a route from Syrjälä to Lehmälä.

First print an integer $k$: the number of critical cities. After this, print $k$ integers: the critical cities in increasing order.

- $2 \le n \le 10^5$

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

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

Input:

`5 5`

1 2

2 3

2 4

3 5

4 5

Output:

`3`

1 2 5