x = int(input())
y = int(input())
l = int(input())
abs_x = abs(x)
abs_y = abs(y)
if abs_x % l == 0:
    n_x = abs_x // l
else:
    n_x = abs_x // l + 1
if abs_y % l == 0:
    n_y = abs_y // l
else:
    n_y = abs_y // l + 1
if y < 0:
    ans = n_x + n_y + 2
elif y > 0:
    if x == 0:
        ans =  n_x + n_y
    else:
        ans =  n_x + n_y + 1
else:
    if x == 0:
        ans =  n_x + n_y
    else:
        ans =  n_x + n_y + 1
print(ans)