type ABC(stream:System.IO.TextReader) =
  member this.Scan1 f = stream.ReadLine() |> f
  member this.Scan2 f = stream.ReadLine().Split() |> Array.map f |> (fun a -> (a.[0], a.[1]))
  member this.Scan3 f = stream.ReadLine().Split() |> Array.map f |> (fun a -> (a.[0], a.[1], a.[2]))
  member this.Scan4 f = stream.ReadLine().Split() |> Array.map f |> (fun a -> (a.[0], a.[1], a.[2], a.[3]))
  member this.ScanVecH f = stream.ReadLine().Split() |> Array.map f
  member this.ScanVecV n f = [| for i in 1..n -> stream.ReadLine() |> f |]
  member this.ScanMatrix n f  = [ for i in 1..n do yield stream.ReadLine().Split() |> Array.map f ]
  member this.ScanCharMatrix n = [| for i in 1..n -> stream.ReadLine().ToCharArray() |]
  member this.Close () = stream.Close()

let util = ABC(stdin)
  
util.Scan1 int |> ignore
let hs = util.ScanVecH int

// ttfftf -> 2
let rec rcount flg cnt xs =
  match xs with
  | [] -> cnt
  | x::xs ->
      match x with
      | true -> rcount true (cnt+(if flg then 0 else 1)) xs
      | false-> rcount false cnt xs

[
  for h in 1..100 ->
    hs
    |> Array.map (fun x -> x >= h)
    |> Array.toList
    |> rcount false 0
]
|> List.sum
|> printfn "%d"

