import sys

sys.setrecursionlimit(10 ** 8)

input = sys.stdin.readline


def main():
    N, K = [int(x) for x in input().split()]
    A = [int(x) for x in input().split()]

    A.sort(reverse=True)

    ans = 0
    for i in range(K):
        if A[i] <= 0:
            break
        ans += A[i]

    print(ans)





if __name__ == '__main__':
    main()