import java.util.Scanner;

public class Passwd {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		Scanner input = new Scanner(System.in);
		int n = input.nextInt();
		String s = input.next();
		char[] str = new char[60];
		for(int i = 0;i<s.length();i++) {
			if(n==26) {
				System.out.println(s);
				break;
			}
			str[i] = (char) (s.charAt(i)+n);
		}
		for(int i = 0;i<str.length;i++) {
			System.out.print(str[i]);
		}
	}

}