n, k, x = map(int, input().split())
a = list(map(int, input().split()))

score = -x

counter = []
for i in range(1, n+1):
	count = min(k, i)
	
	ba = a[:i]
	ba.sort(reverse = True)
	
	counter.append(sum(ba[:count]))

for i in range(1, n+1):
	"""
	scoref = []
	
	
	ba = a[:i]
	ba.sort(reverse = True)
	
	for j in range(min(k, i)):
		scoref.append(ba[j])
	
	curr_score = sum(scoref) - x*i
	"""

	curr_score = counter[i-1] - x*i
	
	score = max(curr_score, score)
	
	
print(score)