I have a INDEX/MATCH formula, whenever it encounters a duplicate, it is being ignored. Otherwise it works fine
=IFERROR(IF(COUNTIF($J$3:J3,J3)=1,MATCH(J3,INDEX(Input_Events,,5),0),MATCH(J3,INDEX(INDIRECT(ADDRESS(ROW(Input_Events)+K2,6,1,1)):data!$J$102,,2),0)+K2),"")
Thanks