
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
Determine the value of the expression

$$
1+2-3+4+5-6+7+8-9+10+11-12+\cdots+94+95-96+97+98-99
$$

(The expression consists of 99 terms. The operations alternate between two additions and one subtraction.)

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