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

char buf1[200000], buf2[200000];
char buf3[200000];

int main()
{
	while (true) {
		fgets(buf1, 200000, stdin);
		buf1[strlen(buf1) - 1] = '\0';
		if (strcmp("0", buf1) == 0) break;
		
		fgets(buf2, 200000, stdin);
		buf2[strlen(buf2) - 1] = '\0';

		int l1 = strlen(buf1);
		int l2 = strlen(buf2);
		for (int i = 0; i < l2; i++) {
			buf3[i] = (buf2[i] -'A' + buf1[i % l1] - 'A' + 1) % 26 + 'A';
		}
		buf3[l2] = '\0';
		printf("%s\n", buf3);
	}
}