Formula needed

[Rob123]

I have a excel spreadsheet with 3 sheets (to keep it simple)

Sheet 1 has some peoples names
Sheet 2 has more names
Sheet 3 has more names

Basically some of the names on sheet 3 appear in sheet 1 and 2 - theres a column on sheet 3 to say "yes" they do appear or "no" they dont. I need a formula so that it can see if (e.g.) cell A2 on sheet 3 appears on sheet 1 or 2.

Thanks for any help and advice

[daddylonglegs]

Assuming your names are only on column A on each sheet

perhaps use this in sheet3!B2 copied down

=IF(COUNTIF(sheet1!A:A,A2)+COUNTIF(sheet2!A:A,A2),"Yes","No")