Trying to mark duplicates on google sheets, but I see that First Instance is highlighted when I use 

```
=COUNTIF(A1:A100, A1)>1.

```

I tried to use IF and COUNTIF together so that the 2nd Instance gets highlighted.

```
=IF(COUNTIF(A1:A97,A1)>1, "Duplicate", " ") 

```

but did not work.

I am trying to use this so that the cell gets highlighted as soon as I enter the duplicate number in the column.