
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
During an Everest expedition, participants set up four high-altitude camps (not counting the base camp), each a day's journey apart, and then descended to the base. After reassessing supplies, the leader decided that an additional oxygen cylinder needed to be placed in the fourth camp, requiring everyone to climb again.

Conditions:
1) A person can carry no more than three oxygen cylinders at a time.
2) A person consumes exactly one oxygen cylinder per day.

What is the minimum number of oxygen cylinders that need to be taken from the base camp to achieve this goal?
(Note: Cylinders can be left only in the camps.)

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