def main():
    n, k = map(int, input().split())
    A = sorted(map(int, input().split()), reverse=True)
    if A[0] < 0:
        print(A[0])
        return
    *A, = filter(lambda x: x > 0, A)
    print(sum(A[:min(len(A), k)]))


if __name__ == '__main__':
    main()