
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
On a plane several straight lines are drawn in such a way that each of them intersects exactly  $15$  other lines. How many lines are drawn on the plane? Find all possibilities and justify your answer.

Poland

Present the answer in LaTex format: \boxed{Your answer}
user