
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
There are 6 students standing in a row. How many different arrangements are there that meet the following requirements? (The result should be given as a number.)  
(1) Student A does not stand at the head, and student B does not stand at the tail;  
(2) Students A, B, and C are not adjacent to each other;  
(3) Students A and B are adjacent, and students C and D are adjacent;  
(4) Neither A nor B is adjacent to C.

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