import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

n, k, *a = map(int, read().split())
a.sort()
ans = max(a)
for i in range(n):
    if a[0] < 0:
        a.pop(0)
    else:
        break
a.sort(reverse=True)
print(max(ans, sum(a[:k])))