n = int(input())
k = int(input())
A = [int(input()) for _ in range(n)]

import itertools, math
ans = -10**18
for p in itertools.product(range(k), repeat=n):
    X = [[] for _ in range(k)]
    for i in range(n):
        X[p[i]].append(A[i])
    M = -10**18
    m = 10**18
    flag = True
    for x in X:
        if not x:
            flag = False
            break
        M = max(M, sum(x)/len(x))
        m = min(M, sum(x)/len(x))
    if flag:
        ans = max(ans, M-m)
print(math.ceil(ans))