
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 a test, the teacher gave five problems and awarded a grade equal to the number of problems solved. All students, except Peter, solved the same number of problems, and Peter solved one more problem. Nine students solved the first problem, seven solved the second, five solved the third, three solved the fourth, and one solved the fifth.

How many grades of four and five were given on the test?

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