
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 person has 5 keys, among which only one is the key to the door, but he forgot which one can open the door, so he has to try them one by one. The probability that he opens the door exactly on the third attempt is     .

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