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 N = read int let A = reada int64 seq { for i in 0 .. 2 .. 2 * (N - 1) do yield abs (A.[i] - A.[i + 1]) } |> Seq.sort |> fun s -> if N <= 2 then Seq.sum s else (Seq.tail s |> Seq.sum) - (Seq.head s) |> puts () // ----------------------------------------------------------------------------------------------------- main() writer.Dispose()