import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class vigenere
{
	public static void main(String[] args) throws Exception
	{
		StringTokenizer st;
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		String line1;
		String line2;
		while(true)
		{
			line1 = br.readLine();
			if(line1.compareTo("0") == 0) break;
			line2 = br.readLine();
			int pos=0;
			for(int i = 0; i < line2.length();i++)
			{ 
				if(pos>=line1.length()) pos = 0;
				
				int znak = line2.charAt(i)+line1.charAt(pos)-64;
				if(znak-65 >= 26) znak+=-26;
				//System.out.println(line2.charAt(i)+" = "+(int)line2.charAt(i));
				sb.append((char)znak);
				pos++;
			}
			sb.append("\n");
			
		}
		System.out.println(sb.toString().trim());
		sb = new StringBuilder();
		
	}
}