Scanf.scanf "%d %d %d" (fun x y l ->
    let ll k = (abs k + l - 1) / l in
    Printf.printf "%d\n" @@
    match y >= 0, x = 0 with
    | true,  true  -> ll x + ll y     
    | true,  false -> ll x + ll y + 1
    | false, true  -> ll x + ll y + 2
    | false, false -> ll x + ll y + 2
)