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

  
let num = List.head args

let rec concat lt =
    match lt with
    | [] -> ""
    | x::xs -> x.ToString() + (concat xs)

let ress = concat [0..num ]

printfn "%c" (ress.ToString()).[num]