# input
N = int(input())
K = int(input())
n = [int(input()) for i in range(N)]

ans = 0

# 3bitで全探索
for i in range(3**N):
	g1 = []
	g2 = []
	g3 = []

	x = i
	for j in range(N):
		if(x % 3 == 0):
			g1.append(n[j])
		elif(x % 3 == 1):
			g2.append(n[j])
		else:
			g3.append(n[j])
		x //= 3
	
	# 正しいグループかどうか判定
	if(len(g1) > 0 and len(g2) > 0 and len(g3) > 0):
		ave1 = sum(g1) // len(g1)
		ave2 = sum(g2) // len(g2)
		ave3 = sum(g3) // len(g3)

		# 平均3つのうち、最大-最小を更新
		ave_l = sorted([ave1, ave2, ave3])
		ans = max(ans, (ave_l[2] - ave_l[0]))

print(ans)