public class move {
    public static void main(String[] args) {
        Scanner n=new Scanner(System.in);
        Scanner a=new Scanner(System.in);
        Integer n1=n.nextInt();
        String a1=a.next();
        String a2=a1.replaceAll(" ","");
        for(int i=0;i<a2.length();i++){
            char ch=a2.charAt(i);
            if(ch<='z'&&ch>='a'){
                n1=n1%26;
                char ch1=(char)(ch+n1);
                if(ch1>'z'){
                    char ch2=(char)(ch1-26);
                    System.out.print(ch2);
                }else {
                    System.out.print(ch1);
                }
            }
        }
        n.close();
        a.close();
    }
}