
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
The set of values of variable $x$ is $\{-21, -20, -19, \ldots, 17, 18\}$, and the set of values of variable $y$ is $\{-3, -4, \ldots, -13, -14\}$. How many different values can the variable $x + y$ take? What is the sum of the highest and lowest values of $x + y$?

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