import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StringWriter;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author cteam66
 */
public class vigenere {
        public static String vig(String encode, String ret)
        {
            String code = "";
            int velikostKodu = encode.length();
            int velikostRet = ret.length();
            int[] codeInt = new int[velikostKodu];
            for(int j = 0; j < velikostKodu; j++)
            {
                codeInt[j] = (int) encode.charAt(j);
            }
            
            int pomKey = 0;
            for(int i = 0; i < velikostRet; i++ )
            {
                int pozice = (int) ret.charAt(i);
                int codeS = codeInt[pomKey];
                pozice = pozice + (codeS - 65) + 1;
                if(pozice > 90)
                {
                    pozice = 65 + (pozice - 91);
                }
                
                code += (char) pozice;
                pomKey++;
                if(pomKey >= velikostKodu) pomKey = 0;
            }

            return code;
        }
    
        public static void main(String [] args) throws IOException
        {
          //  System.out.print((int) 'A'+"");
            StringWriter sw = new StringWriter();
            BufferedReader bfr = new BufferedReader(new InputStreamReader(System.in));
            String line = bfr.readLine();
            while(!line.equals("0")) {
                String text = bfr.readLine();

                sw.append(vig(line, text)+"\n");
                line = bfr.readLine();
            }
            System.out.print(sw);
        }
}