
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
In the painting exhibition organized by the school, the first grade contributed 20 pieces, the second grade contributed 45 pieces, and the third grade contributed 17 pieces fewer than the total of the first and second grades. The fourth grade contributed 36 pieces fewer than twice the amount of the third grade.  
Question ①: How many pieces did the third grade contribute?  
Question ②: How many pieces did the fourth grade contribute?

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