UITableView中的两种不同类型的自定义uitableviewcell

in my UITableView i want to set for the first news of an rss feed a custom tableViewCell(Type A lets say) and for the other news second, third etc.. another custom tableViewCell(trype B) the problem is that the custom tableViewCell(trype A) created for the first news is reused, but curiously the number of rows between the first use of the customViewCell(type A) and the second appearance of the same type of customViewCell is not equal..in my UITableView i want to set for the first n