# A

N, K = list(map(int, input().split()))
As = list(map(int, input().split()))
positives = [a for a in As if a >= 0]
negatives = [a for a in As if a < 0]

if positives:
    selected = positives
else:
    selected = [sorted(negatives)[-1]]

selected = sorted(selected)
selected = selected[-min(K, len(selected)):]
print(sum(selected))