n, k = map(int, input().split())
a = list(map(int, input().split()))
flag = True
for i in range(n):
    if a[i] > 0:
        flag = False
if flag:
    print(max(a))
else:
    for i in range(n):
        if a[i] < 0:
            a[i] = 0
    print(sum(sorted(a)[n-k:n]))