#define debug if(1)
#include <cstdio>
#include <cstring>

#define REP(i,n) for(int i = 0; i < int(n); i++)

const int maxn = 100100;
int n,m;
char text[maxn];
char cipher[maxn];
char res[maxn];
const int s = 'Z' - 'A' + 1;

int main() {
	while(true) {
		scanf("%s", cipher);
		if(strcmp(cipher,"0") == 0) break;
		scanf("%s", text);
		n = strlen(text);
		m = strlen(cipher);
		int j = 0;
		REP(i,n) {
			res[i] = 'A' + ((text[i] - 'A') + (cipher[j] - 'A') + 1) % s;
			j = (j + 1) % m;
		}
		res[n] = 0;
		printf("%s\n", res);
	}
	return 0;
}