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*<=&gt;<=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<=<=≤<=*n*<=<=≤<=5000,<=0<=≤<=*k*<=≤<=4), which we have mentioned above. 

The second line contains *n* distinct integers *a*1,<=*a*2,<=...,<=*a**n* (0<=≤<=*a**i*<=≤<=106).
Print a single positive integer — the minimum *m*.
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