n,k = map(int,input().split())
an = sorted(list(map(int,input().split())))[::-1]
count = an[0]
i_c = 1
for i in range(1,len(an)):
    if an[i]<0 or i_c>=k:
        break
    else:
        count+=an[i]
        i_c+=1
print(count)