
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
Laura and her three younger siblings each want a new cellphone for their birthdays. Laura insists on having a service from Verizon, while her siblings want different providers from each other and none of them wants Verizon. There are in total 25 service providers. In how many ways can their parents purchase the cellphones satisfying all conditions?

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