How to count according to every third cell value in a row?

I have a row range, in which I'd like to take into consideration every 3rd cell value in it.
Every third cell can have the following values: 0, 1 or more and empty (I will set it as _ in the examples below)

The valid combinations can be as following:
_
0,_
0,0,_
>0
0,>0
0,0,>0
etc.

I'd like to have the following outcome:

When there are 0 or more 0's with a following empty cell - NA
When there is one >0 - ==> 1
When there are one or more 0's followed by one >0 cell - # of 0's + 1
There cannot be more than one >0 cell, and it is always after (0 or more) zeros.

Examples.
Remember: I am only interested in the values of C, F and I etc.

A	B	C	D	E	F	G	H	I	outcome
x	x								NA
x	x	0	x	x					NA
x	x	0	x	x	0	x	x		NA
x	x	20							1
x	x	0	x	x	10				2
x	x	0	x	x	0	x	x	300	3

I hope that the pattern is clear.
Again, for each third cell in a row:
As long as there only empty cells or zeros ==> NA
When there is one >0 cell and before it 0 or more zeroed cells => Number of zeros + 1

I can show you many options I tried, but none worked.
So I'd ask for you assitance.

Do the irrelevant cells contain EITHER an X or a blank???

This works for me with Office 365... Will it work for you??

=IFERROR(AGGREGATE(14,6,{1,2,3}/(INDEX($A4:$I4,,{3,6,9})>0),1),"NA")

copied down.

You seem to be using an older version of Excel than me. So, please refer to the attached file. If the formulae are enclosed within a pair of { }, these are array formulae.

These are a little different from ordinary formulae in that they MUST be confirmed in the FIRST CELL ONLY by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER. After that, the array can be dragged down as normal, to cover the desired range.

You will know the array is active when you see the curly brackets { } appear around the outside of your formula. If you do not use CTRL+SHIFT+ENTER you will (almost always) get an error message or an incorrect answer. Press F2 on that cell and try again.

Don't type the curly brackets yourself - it won't work...

In the end (I think) my Q was irrelevant... assuming that the approach at Post 3 works for you.

Did you see the file, attached at Post 3??

OK for me... what do you mean by a format error???

No idea. I don't use Google sheets. If you had wanted it to work in GS... you should have posted it in the "Other platforms" sub-forum... or made it clear that you wanted a GS solution.

You're welcome.

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It would be very nice if you were to just click the Add Reputation button at the foot of any of the posts of members who helped you reach a solution.

Finally, if that takes care of your original question, please select "Thread Tools" from the menu link (just above the first post in the thread) and mark this thread as SOLVED.

No problem!! Enjoy what's left of the weekend.