function Main(input) {
  var chars = input.trim().split('\n');

  var alfa = '0ABCDEFGHIJKLMNOPQRSTUVWXYZ';

  var migi = Math.floor(chars[0]);
  var str = chars[1].split('');

  var nums = [];
  var ans = '';

  str.forEach(n => {
    var temp = alfa.indexOf(n);
    temp += migi;
    while (temp >= 27) {
      temp -= 26;
    }
    nums.push(temp);
  });

  nums.forEach(n => {
    ans += alfa[n];
  });

  console.log(ans);
}
Main(require('fs').readFileSync('/dev/stdin', 'utf8'));
