#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <cctype>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
using namespace std;

#define DEBUG(x) cout << '>' << #x << ':' << x << endl;
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FOR2(i, a, b) for (int i = (a); i > (b); --i)
inline bool EQ(double a, double b) { return fabs(a-b) < 1e-9; }

const int INF = 1<<29;
typedef long long ll;

char key[1007], message[100007];

int main() {
	while (true)
	{
		scanf("%s", key);
		if (key[0] == '0') break;
		scanf("%s", message);
		
		int len1 = strlen(key), len2 = strlen(message);
		FOR(i, 0, len2)
		{
			int c = message[i]-'A', d = key[i%len1]-'A'+1;
			c = (c+d) % 26;
			message[i] = c+'A';
		}
		printf("%s\n", message);
	}
	return 0;
}