
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 school offers elective courses, including 4 humanities courses ($A\_1$), ($A\_2$), ($A\_3$), ($A\_4$), and 3 natural science courses ($B\_1$), ($B\_2$), ($B\_3$). Among them, the class time of ($A\_1$) and ($B\_1$) coincides, and the rest do not conflict. A student chooses a total of 3 courses. If it is required to choose at least one course from each category, then the student has a total of $\_\_\_\_\_\_\_\_$ ways to choose courses. (Fill in the blank with a number)

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