excel – Match and update Value of one cell in sheet 2 to using values in different sheets

I have a excel file which has 5 sheets .
My requirement is

If sheet 3,4,5 A2 is N/A I have to update that same N/A in Sheet 2 E18-21 .
So everytime if A2 is equal to N/A in different sheets . I have to use that or update in sheet 2 certain cells.

Please let me know which formula can satisfy this condition.