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

F = [int(x) for x in input().split()]
F = sorted(F,reverse=True)
ans = 0
for i in range(K):
    if F[0] <= 0 :
        ans = F[0]
        break
    else:
        if F[i]>0:
            ans += F[i]
        else:
            break

print(ans)