#coding=UTF-8
#後先のこと考えずに貪欲にやればいいはず

X=int(input())
Y=int(input())
L=int(input())

hoko=[(0,1),(-1,0),(0,-1),(1,0)]
ans=0

if Y>=0:
    if Y % L ==0:
        ans=ans+Y//L
    else:
        ans=ans+Y//L+1

    if X==0:
        pass
    else:
        ans=ans+1
        if abs(X)% L==0:
            ans=ans+abs(X)//L
        else:
            ans=ans+abs(X)//L+1
else:
    ans=ans+1
    if abs(X)% L==0:
        ans=ans+abs(X)//L
    else:
        ans=ans+abs(X)//L+1

    ans=ans+1
    if abs(Y)%L==0:
        ans=ans+abs(Y)//L
    else:
        ans=ans+abs(Y)//L+1
        
print(ans)