#include <iostream>
#include <string>

using namespace std;

int main()
{
    string s1,s2;
    cin >> s1;
    while ( s1 != "0" )
    {
	cin >> s2;
	string coded = "";
	int s1length = s1.length();
	for ( int i = 0; i < s2.length(); i++ )
	{
		char thisChar = (s2[i]-'A')+(s1[i%s1length] - 'A'+1);
		thisChar %= 26;
		thisChar = 'A' + thisChar;
		coded += thisChar;
	}
	cout << coded << endl;
	cin >> s1;
    }
	return 0;
}