import java.util.*;
import java.io.*;

public class vigenere{


public static void main(String[] args) throws IOException{
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String line;
	String kljuc;
	String beseda;
	int novaCrka2;
	while(!(line = br.readLine()).equals("0")){
		kljuc = line;
		beseda = br.readLine();
		novaCrka2 = 0;
		for(int i = 0; i < beseda.length(); i++){
			novaCrka2 = ((((int)kljuc.charAt(i % kljuc.length())) + ((int)beseda.charAt(i)) -128) % 26) + 64;
			if(novaCrka2 == 64){
				novaCrka2 = 90;
			}
			System.out.print((char)novaCrka2);
		}
		System.out.println("");
	}	

}
}