Check first name and surname in one worksheet against first name and surname in second worksheet and bring back YES if the name is on both lists

[melsmiff]

I have 2 worksheets, one with a list of names of people who registered for an event, and one with a list of names for those who actually turnedup. I am trying to find a formula to Check one worksheet against the other and bring back YES if the name is on both lists. The names are split into first name and surname

 

[etaf]

assuming in A and B on sheet1 & Sheet2
comparing Sheet1 with 2
=COUNTIFS(Sheet2!A:A, Sheet1!A2, Sheet2!B:B, Sheet1!B2)
then use an IF
=IF ( COUNTIFS(Sheet2!A:A, Sheet1!A2, Sheet2!B:B, Sheet1!B2) = 1 , "YES", "NO" )