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 y
    | true,  false -> ll y     + 1 + ll x
    | false, true  -> 1        + 1 + ll y
    | false, false -> 1 + ll x + 1 + ll y
)