open System

let f (len: int) (str: string): string =
    if str.Length <= len then 
        str 
    else 
        str.ToCharArray()
        |> Array.take len
        |> Array.map string 
        |> String.concat ""
        |> fun s -> s + "..."

let K = Console.ReadLine() |> int 
let S = Console.ReadLine()

f K S 
|> printfn "%s"