Code Help - How to place statement after each 1st post

[kau]

I want to put some code after the first post on every page.

I've found code that will put a statement after the first post;

<if condition="$post[postcount] == 1">

However, this only does it once. When the user clicks Page 2 I want the ad to show again after 1st post on that page. Has to be dynamic though since users can choose how many posts per page they see.

Anyone know?