In 1975, Lander showed that there exist some languages in NP NPC P (denoted as NPI) under the assumption P≠NP. But the language constructed there is indeed an unnatural one because the construction needs to run all polynomial time Turing machines. So far, no natural problems have been proved to be in NPI under P≠NP and finding a natural problem in NP NPC P is indeed an important open problem. In this paper this long open problem is partially solved. A 2+ f(m) HSAT model is defined. Based on this model,a candidate for natural problems in ((NP-NPC)-P),denoted as NPI,under the assumption P≠NP is given,and the authors have proven that it is not in NP-Completer P≠NP.Actually,it indeed is in NPI under some stronger but plausible assumption.In comparison,similar for the two other candidates,GI and Facting,are not known.