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)
      num2Alpha((num+n)%26)
    }.toUpperCase()
  }

  // 0 index
  def num2Alpha(n: Int): Char =
    ('a' + 0).toChar

  // 0 index
  def alpha2Num(c: Char): Int =
    c - 'a'

  println(solve())

}

