
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
A and B are running back and forth on a 120-meter straight road. A's speed is 5 meters per second, and B's speed is 3 meters per second. If they start running from the same end at the same time and run for 15 minutes, how many times do they meet head-on during this period (excluding the endpoints)?

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