#include<cstdio>
#include<cstring>

int main() {
	while(true) {
		char code[200000];
		char text[200000];
		scanf("%s",code);
		if(strcmp(code,"0")==0) break;
		scanf("%s",text);
		int len = strlen(code);
		for(int i=0;text[i];i++) {
			char a = text[i];
			char b = code[i%len];
			char c = ((a-'A')+(b-'A')+1)%26 + 'A';
			putc(c,stdout);
		}
		putc('\n',stdout);
	}
	return 0;
}