League of Overwatch at Moloco (Easy)

Every so often the employees of Moloco split into two groups and play a best of five series of League of Overwatch. Some pairs of employees are hardcore gamers who have already played together as a duo, so the company separates each such pair for this event to keep it enjoyable for beginners.

Moloco has $n$ employees, numbered 1 through $n$.

There are $m$ known pairs $(f_i, s_i)$: employees $f_i$ and $s_i$ played a duo game in the past, so they must end up in different groups.

Decide whether the $n$ employees can be split into two non-empty groups so that every employee belongs to exactly one group and no pair $(f_i, s_i)$ has both of its members in the same group.

The first line contains two integers $n$ and $m$ ($1 \le n \le 16$, $1 \le m \le 150$).

Each of the next $m$ lines contains two integers $f_i$ and $s_i$ ($1 \le f_i, s_i \le n$). It is guaranteed that $f_i \ne s_i$ for every $i$. The same pair can appear more than once.

Print one line containing either POSSIBLE or IMPOSSIBLE.

In the second example, splitting the employees into $\{2\}$ and $\{1, 3\}$ satisfies every constraint.