X,Y,L=map(int,(input(),input(),input()))
a=0

if X!=0:
    X=max(X,-X)
    a+=1#rot
    a+=X//L+(X%L!=0)#move
elif Y<0:
    a+=1#rot

if Y<0:
    Y=-Y
    a+=1#rot
a+=Y//L+(Y%L!=0)#mov
print(a)