import java.util.*

fun main(args: Array<String>) {
    val read = Scanner(System.`in`)

    val alphabetList = "abcdefghijklmnopqrstuvwxyz".toUpperCase()
    val n = read.nextInt()
    val s = read.next()
    var o :String = ""

    for(i in s.split("").filter { it != "" }) {
        var originIndex = alphabetList.indexOf(i)
        var nextIndex = (originIndex + n) % 26
        o += (alphabetList[nextIndex])
    }

    println(o)
}