
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
Consider the series expressions 
\[C = 1^2 \times 2 + 3^2 \times 4 + 5^2 \times 6 + \cdots + 37^2 \times 38 + 39^2\]
and 
\[D = 1 + 2^2 \times 3 + 4^2 \times 5 + \cdots + 36^2 \times 37 + 38^2 \times 39.\]
Find the positive difference between integers $C$ and $D$.

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