
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
A large supermarket sells four types of dairy products: pure milk, yogurt, infant formula, and adult milk powder. There are 30, 10, 35, and 25 different brands for each type respectively. Using stratified sampling, a sample of size $n$ is drawn for melamine safety testing. If 7 brands of infant formula are sampled, then $n = \boxed{?}$.

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