import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	N, K = getlist()
	A = list(sorted(getlist()))
	ans = 0
	for i in range(K):
		if A[-1 - i] > 0:
			ans += A[-1 - i]
		else:
			break

	print(ans)

if __name__ == '__main__':
	main()