If Statement across multiple sheets in Excel

I have been trying to get this working for the past 2 hours but I am stuck.

Background: I am doing an audit of our sites and want a Master sheet which shows the health of the audit.

Problem: I have 4 sheets, 1 called Master and the other 3 called London, Edinburgh and Dublin. Here is what I am trying to do.

If cell B3 in sheets London, Edinburgh and Dublin has the word yes, I want cell B3 in Master to turn Green. If the 3 sheets have even 1 No, then it should turn yellow and if 2 or more are No then B3 in Master should turn red.

So far I have this and it isn't working. I cant seem to figure out how to match data in more than 2 sheets, definitely no idea how to do what I described above. I believe I need arrays but my excel knowledge is limited.

=IFERROR(IF(MATCH(London!B3 & Edinburgh!B3, Master!$A:$A,0),"yes",),"no")

Would appreciate any help.

Thanks Neha