
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
The domestic postage standard for mailing printed materials in China is as follows: 0.7 yuan for up to 100g, and an additional 0.4 yuan for each increment of 100g (less than 100g is treated as 100g). How much should a person pay to mail a book weighing 420g from Mianyang to Shanghai?

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