Searching Multiple Columns to Calculate Severity

I have spreadsheet to assess risk in a given situation. There are multiple columns (AA-AO) that have different conditions, and if "y" is marked then it meets that condition. What I want to do is calculate if the person is "low," "medium," or "high risk" and display that in a cell.

Low Risk columns AA-AE
Medium Risk columns AF-AL
High Risk Columns AM-AO

If there is a "y" in one of the high columns, then I want to display "high," even if it also has a "y" in the low or medium columns, because I want the greatest risk to be displayed.

I know how to do this individually for each set of columns, but I am sure that it is not very efficient. I don't know how to combine them or nest the formulas correctly. This may not be the most elegant or efficient solution, but this is as far as I have gotten.

=IF(OR($AA4="y",$AB4="y",$AC4="y", $AD4="y",$AE4="y"),"y","")
=IF(OR($AF4="y",$AG4="y",$AH4="y",$AI4="y",$AJ4="y",$AK4="y",$AL4="y"),"y","")
=IF(OR($AM4="y",$AN4="y",$AO4="y"),"y","")

I would so appreciate any help with this.

Thank you so, so much for your quick response! You are a lifesaver!

As a bonus question... Is there a way to add something to the formula where, if there was nothing in any of the fields (AA4-AO4) that it would return "none"? I did not think of that before.

Thank you so much! I spent a long time trying to figure this all out, and you saved me a lot more time. Thank you for sharing your knowledge!