First time visiting a page

Hi does anyone knows if it's possible to know the number of visits/unique visitors (metric doesn't matter) who visits a certain page for the first time? It's not related to first/return visits, but a single page visited for the first time. A user who has accessed a web site 20 times can see a page A in the visit number 15. What I need is a segment which indicates that the user watched the page A for the first time and (for example) bought 3 days later (the 3 days later is easy, but I don't know how to create the first part from the segment).

Thanks!