
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
Given that 63 students wear red shirts and 81 students wear green shirts, and the 144 students are divided into 72 pairs, while 27 of these pairs consist of two students wearing red shirts, find the number of pairs with two students wearing green shirts.

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