module Yuki

open System

let solve x y r =
    let x = abs x
    let y = abs y
    let rd = (float r) * Math.Cos (Math.PI / 4.0) |> (*) 2. |> Math.Ceiling |> int    
    x + y + rd

let x, y, z =
    let str = Console.ReadLine().Split() |> Array.map int
    str.[0], str.[1], str.[2]

solve x y z
|> Console.WriteLine