function Main(input) {
  var inputs = input.split('\n')
  var number = inputs[0]

  if (number === 0) {
    console.log(inputs[1])
    return
  }
  var strings = inputs[1].split('')
  var c = 'A'.charCodeAt(0)
  var alphabet = Array.apply(null, new Array(26)).map((v, i) => {
    return String.fromCharCode(c + i);
  })

  var alpToNum = {}
  var numToalp = alphabet
  for (i = 0; i < alphabet.length; i++) {
    alpToNum[alphabet[i]] = i
  }

  var result = []

  for(j=0; j < strings.length; j++) {
    var num = (alpToNum[strings[j]] + parseInt(number)) % 26
    result[j] = numToalp[num]
  }
  result = result.join('')
  console.log(result)
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));