
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
Write 2004 numbers on the blackboard: $1, 2, \cdots, 2004$. In each step, erase some numbers and write their sum modulo 167. After several steps, among the two numbers remaining on the blackboard, one of them is 999. What is the other number?

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