X=int(raw_input())
Y=int(raw_input())
L=int(raw_input())
xlflag = 1
ylflag = 1
xflag = 0
if(X%L==0):
	xlflag = 0
if(Y%L==0):
	ylflag = 0
 
if(X==0 and Y>=0):
	xflag =0
elif(X!=0 and Y>=0):
	xflag = 1
else:
	xflag = 2
 
print(xflag+int(abs(X)/L)+xlflag+int(abs(Y)/L)+ylflag)