
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
In the Cartesian coordinate system $xOy$, it is known that the initial sides of angles $\alpha$ and $\beta$ are the non-negative half-axis of $x$, and their terminal sides pass through points $A(1,2)$ and $B(5,1)$, respectively. The value of $\tan (\alpha-\beta)$ is __________.

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