#include <cstdio>
#include <cstring>
int main() {
	char key[1001], plaintext[100001];
	while (true) {
		scanf("%s", key);
		if (strcmp(key, "0") == 0) break;
		scanf("%s", plaintext);
		for (int i = 0, _i = (int)strlen(plaintext), j = 0, _j = (int)strlen(key); i < _i; i++) {
			int p = key[j] - 'A' + 1;
			int c = 'A' + ((plaintext[i] - 'A' + p) % 26);
			printf("%c", c);
			j++;
			if (j >= _j) j = 0;
		}
		puts("");
	}
	return 0;
}