x=int(input())
y=int(input())
n=int(input())
c=0
if y>0:
    if y%n==0:
        c+=y//n
    else:
        c+=y//n+1
    if x>0:
        if x%n==0:
            c+=x//n+1
        else:
            c+=x//n+2
    elif x<0:
        if -x%n==0:
            c+=-x//n+1
        else:
            c+=-x//n+2
elif y==0:
    if x>0:
        if x%n==0:
            c+=x//n+1
        else:
            c+=x//n+2
    elif x<0:
        if x%n==0:
            c+=-x//n+1
        else:
            c+=-x//n+2
else:
    if -y%n==0:
        c+=-y//n
    else:
        c+=-y//n+1
    if x>0:
        if x%n==0:
            c+=x//n+1
        else:
            c+=x//n+2
    elif x<0:
        if -x%n==0:
            c+=-x//n+1
        else:
            c+=-x//n+2
print(c)