
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 certain city plans to assign four individuals: A, B, C, and D to three different grassroots units for job rotation training, with each unit receiving at least one individual. Moreover, individuals A and B cannot be assigned to the same unit. The number of different possible assignment methods is ______.

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