let inputs = System.Console.ReadLine().Split(' ')
let args = [for str in inputs do yield int(str) ]

let rec contains f lt =
  match lt with
  | [] -> false
  | x::xs -> if f x  then  true else contains f xs

let rec filter f lt =
  match lt with
  | [] -> []
  | x::xs -> if f x then  [x] @ (filter f xs) else filter f xs


let contests = [23..25]
let dups = filter (fun  x -> contains (fun y -> y = x ) contests ) [ (List.head args) .. (List.item 1 args) ]

printfn "%i" (contests.Length - dups.Length)