
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 long bench, a boy and a girl were sitting. One by one, 20 more children approached them, and each sat between two children already sitting there. We call a girl "brave" if she sat between two neighboring boys, and a boy "brave" if he sat between two neighboring girls. When everyone was seated, it turned out that boys and girls were sitting on the bench alternately. How many of them were brave?

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