
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
Let $a = -\frac{1}{3}$ and $(2a+1)(2b+1)=1$. Find the radian measure of $\arctan a + \arctan b$.
**A)** $\frac{\pi}{2}$  
**B)** $\frac{\pi}{3}$  
**C)** $\frac{\pi}{4}$  
**D)** $\frac{\pi}{6}$  
**E)** $0$

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