search and pagination

[eluser]tzi0[/eluser]
Hi all. I have a problem with my search, dont know how to solve it. I have a form with text input for search string and i want my results was paginated. but it works only if i type search string for the first time and then submit my form (because my search string goes to my script via post, and when i click,for example, second paginated link, my $this->input->post('search_string') stands empty) =(