SILK-ROAD 2004 Problem 4

Natural $n \geq 2$ is given. Group of people calls $n-compact$ , if for any men from group, we can found $n$ people (without he), each two of there are familiar. Find maximum $N$ such that for any $n-compact$ group, consisting $N$ people contains subgroup from $n+1$ people, each of two of there are familiar.