User turns:
user: I'd like to take a look at the finance_report.txt. Would you send me the content of the last line.
user: According to the financial report, what's the mean of revenue and expense and profit. Round to nearest integer and write it in a new file called statistics.txt. Note that only write the integer and nothing else to the text file

Involved APIs: GorillaFileSystem
MathAPI
Ground-truth function call path:
GorillaFileSystem.cd
GorillaFileSystem.touch
GorillaFileSystem.cp
GorillaFileSystem.mv
GorillaFileSystem.grep
GorillaFileSystem.sort
GorillaFileSystem.tail