var input = require("fs").readFileSync("/dev/stdin", "utf8");

var words = input.split('\n');

var N = Number(words[0]);
var S = words[1];

var A_CODE = 'A'.charCodeAt();
var result = '';
for (var i = 0; i < S.length; i++) {
    var charCode = (S[i].charCodeAt() - A_CODE + N) % 26;
    result += String.fromCharCode(A_CODE + charCode);
}
console.log(result);
