#include <stdio.h>
#include <string.h>

int main() {
	while (1) {
		char key[1001];
		char msg[100001];
		
		gets(key);
		
		if (key[0] == '0' && key[1] == '\0')
			break;
		
		gets(msg);
		
		int i, keyLen = strlen(key);
		
		for (i = 0; msg[i] != '\0'; ++i) {
			putchar(((msg[i] + key[i % keyLen] - 2 * 'A' + 1) % 26) + 'A');
		}
		putchar('\n');
	}
	return 0;
}