
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
Given \( x_{1}, x_{2}, \cdots, x_{1990} \) is any permutation of \( 1, 2, \cdots, 1990 \), find the maximum value of the expression
\[ 
\|\cdots\| x_{1}-x_{2}\left|-x_{3}\right|-\cdots\left|-x_{1990}\right| 
\]

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