
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
Determine the difference between the sum of the first $1001$ even counting numbers starting from $4$ and the sum of the first $1001$ odd counting numbers starting from $3$.
A) 1000
B) 1001
C) 1002
D) 1003
E) 2000

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