x = int(input())
y = int(input())
l = int(input())

if x == 0:
    if y >= 0:
        ans = (y+l-1)//l
        print(ans)
        exit()
    else:
        ans = (-y+l-1)//l+1
        print(ans)
        exit()

if y == 0:
    if x > 0:
        ans = (x+l-1)//l+1
        print(ans)
        exit()
    elif x == 0:
        print(0)
        exit()
    else:
        ans = (-x+l-1)//l+1
        print(ans)
        exit()

if x > 0 and y > 0:
    ans = (y+l-1)//l+1+(x+l-1)//l
elif x < 0 and y > 0:
    ans = (y+l-1)//l+1+(-x+l-1)//l
elif x < 0 and y < 0:
    ans = 1+(-x+l-1)//l+1+(-y+l-1)//l
else:
    ans = 1+(x+l-1)//l+1+(-y+l-1)//l
print(ans)