def Main():
    n,k=map(int,input().split())
    ans=0
    a=sorted(map(int,input().split()),reverse=True)
    for i in range(k):
        if a[i]>0:
            ans+=a[i]
    if ans==0 and a[i]<0:
        print(a[i])
        return
    print(ans)
Main()