open System open System.Collections.Generic [] 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())) [] 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 arr = reada int64 let [| a; b; c |] = arr let nax = Array.max arr let na = max a c let ni = min a c match nax = b with | true -> let x = abs (na - ni) let y = abs (na - b) + 1L min x y | false -> let x = abs (na - b) + 1L let y = abs (ni - b) let z = abs (na - ni) List.min [ x; y; z ] |> puts () main() writer.Close()