
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
At each of the four math club sessions, 20 students were present. Nine students attended exactly three out of these four sessions, five students attended exactly two sessions, and three students attended only one session. How many students attended all the sessions?

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