from itertools import permutations
N = int(input())
K = int(input())
n = list(int(input()) for _ in range(N))
L = [i for i in range(N)]
ans = 0
for A in range(1,N+1):
    for B in range(1,N+1):
        if N - A - B < K - 2:
            continue
        for X in permutations(L, A):
            for Y in permutations(L, B):
                flg = True
                for x in X:
                    if x in Y:
                        flg = False
                        break
                if flg:
                    P = sum([n[i] for i in X]) / len(X)
                    Q = sum([n[i] for i in Y]) / len(Y)
                    R = int(P - Q + 0.9)
                    ans = max(ans, R)
print(ans)