main = getContents >>= print . solve . map read . lines

solve :: [Int] -> Int
solve [x, y, l] = a + b + c + d + e
        where
        a = div (abs x) l + if mod (abs x) l == 0 then 0 else 1
        b = div (abs y) l + if mod (abs y) l == 0 then 0 else 1
        c = if y < 0 then 1 else 0
        d = if x == 0 then 0 else 1
        e = if x == 0 && y < 0 then 1 else 0