#include <stdio.h>

int main() {
	char key[1002];
	char plain[100002];
	char *k, *p, c;
	for(;;) {
		scanf("%s", key);
		if( key[0] == '0' ) break;
		scanf("%s", plain);
		k = key;
		p = plain;
		while( *p ) {
			*p -= '@';
			c = ( ( *p + *k - '@' ) % 26 );
			if( c ) c += '@'; else c = 'Z';
			putc( c, stdout );
			k++;
			if( !*k ) k = key;
			p++;
		}
		printf("\n");
	}
}