import sys
sys.setrecursionlimit(100000000)
input = sys.stdin.readline
MOD = 10 ** 9 + 7
INF = 10 ** 15

def main():
    N,K = map(int,input().split())
    A = list(map(int,input().split()))
    A.sort(reverse=True)
    ans = 0
    for i in range(K):
        if A[i] > 0:
            ans += A[i]
    print(ans)
if __name__ == '__main__':
    main()