#include <iostream>
#include <string>
#include <cstdio>

using namespace std;

int main() {
	char buffer[100050];
	string t,k,res;
	while (1) {
		scanf("%s",buffer);
		k=buffer;
		if (k=="0") return 0;
		scanf("%s",buffer);
		t=buffer;
		res="";
		for (int i=0;i<t.length();++i) {
			res+=(t[i]-'A'+k[i%k.length()]-'A'+1)%26+'A';
		}
		printf("%s\n",res.c_str());
	}
}