
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
Given that a square grid of toothpicks is constructed with 15 toothpicks in both the vertical and horizontal directions, and one corner toothpick is missing, calculate the number of toothpicks used.

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