#include <iostream>
#include <string.h>

char key[1001];
char plain[100001];
char result[100001];

int main()
{
	for (;;)
	{
		scanf("%s", key);
		if (key[0] == '0')
			break;
		
		scanf("%s", plain);
		int key_len = strlen(key);
		int plain_len = strlen(plain);

		int j = 0;
		int i;
		for (i = 0; i < plain_len; i++)
		{
			result[i] = plain[i] + (key[j] - 'A') + 1;
			if (result[i] > 'Z')
				result[i] = result[i] - 'Z' + 'A' - 1;
			j++;
			if (j == key_len)
				j = 0;
		}
		result[i] = 0;
		printf ("%s\n", result);
	}	
	return 0;
}