CF303C Minimum Modular

You have been given $ n $ distinct integers $ a_{1},a_{2},...,a_{n} $ . You can remove at most $ k $ of them. Find the minimum modular $ m $ $ (m>0) $ , so that for every pair of the remaining integers $ (a_{i},a_{j}) $ , the following unequality holds: .

The first line contains two integers $ n $ and $ k $ ( $ 1

Print a single positive integer — the minimum $ m $ .