
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
Calculate the sum of digits of all numbers in the sequence $1, 2, 3, ..., 4999$ and find the sum for $5000, 5001, 5002, ..., 9999$ by considering the mirroring effect of each digit from $1$ to $4999$ but with an additional $5$ in the thousands place for each number from $5000$ to $9999$.
- **A**: 450045
- **B**: 474090
- **C**: 500100
- **D**: 525155

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