open System
open System.Collections.Generic

[<AutoOpen>]
module Cin =
    let read f = stdin.ReadLine() |> f
    let reada f = stdin.ReadLine().Split() |> Array.map f
    let readChars() = read string |> Seq.toArray
    let readInts() = readChars() |> Array.map (fun x -> Convert.ToInt32(x.ToString()))

[<AutoOpen>]
module Cout =
    let writer = new IO.StreamWriter(new IO.BufferedStream(Console.OpenStandardOutput()))
    let print (s: string) = writer.Write s
    let println (s: string) = writer.WriteLine s
    let inline puts (s: ^a) = string s |> println

let main() =
    let [| a; b; c |] = reada int64
    let nax = max a c
    let nin = min a c
    let x = 1L + abs (nax - b)
    let y = abs (nax - nin)
    let z = abs (nin - b)
    let t = 1L + abs (nin - b)
    List.min [ x; y; z; t ] |> puts
    ()

main()
writer.Close()