def rainfall():

"""

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Asks the user for daily rainfall (in mm) from the keyboard.

The function stops asking for rainfall when the user enters -1.

The function returns:

the total number of dry days (rainfall lower than 4mm)

the total number of damp days (rainfall 4mm - 8mm)

the total number of wet days (rainfall greater than 8mm)

the average rainfall for all days (rounded down)

Do all inputs and calculations in integer.

Use: dry_days, damp_days, wet_days, avg = rainfall()

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Returns:

dry_days - number of dry days (int)

damp_days - number of damp days (int)

wet_days - number of wet days (int)

avg - average rainfall of all days (int)

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"""

# your code here

return