N, K = map(int, input().split())
A = list(map(int, input().split()))

A.sort(reverse = True)
T = 0

if A[0] < 0 :
    print(A[0])
else:
    for i in range(K):
        if A[i] > 0:
            T += A[i]
        else:
            pass
    print(T)