import scala.io.StdIn._

object Main extends App {


  val n = readInt()
  val s = readLine()

  def solve() = {
    s.map { char =>
      val c = char.toLower
      val num = alpha2Num(c)
      val move = if(n+num > 26) n+num-26 else n+num
      num2Alpha(move)
    }.toUpperCase()
  }

  def num2Alpha(n: Int): Char =
    ('a' + (n-1)).toChar

  def alpha2Num(c: Char): Int =
    ('a' to 'z').indexOf(c) + 1

  println(solve())

}

