
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
For a gift to his son, a father bought 4 books. All the books except the first one cost 84 kopecks, without the second one they cost 80 kopecks, without the third one they cost 76 kopecks, and without the fourth one they cost 72 kopecks. What is the cost of each book?

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