#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <iostream>

using namespace std;

#define BUFLEN 1024

#define a 1
#define z 26


int main(int argc, char *argv[]) {
	argc = argc;
	argv = argv;
	
	{
		char * buff = new char[100010];
		while(true)
		{
			string key,message,result;
			scanf("%s", buff );
			if ( buff[0] == '0' )
				break;
			key = buff;
			scanf("%s", buff);
			message = buff;
			unsigned int kpos = 0;
			for( unsigned int i = 0; i < message.size(); i++ )
			{
				char aux = ( key[kpos++] ) - ( 'A' - 1 );
				kpos = ( kpos >= key.size() ? 0 : kpos );
				char res = message[i] +aux;
				if ( res > 'Z' )
					res -= 26;
				result += res;
			}
			result += "\n";
			printf( result.c_str() );
		}
		delete [] buff;
	}
	
	return 0;
}