from math import ceil
N, K = int(input()), int(input())
s = list(sorted([int(input()) for i in range(N)]))
if N > 2:
    print(s[-1] - s[0])
else:
    print(max([ceil((s[0:i] / i - s[i:N] / (N - i))) for i in range(1, N - 1)]))