#include<cassert>
#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
#include<cmath>
#include<map>
#include<set>
#include<queue>
#include<cstring>
#include<sstream>
#define FORE(it, c) for(__typeof((c).begin()) it = (c).begin(); it != (c).end(); ++it)
#define FC(aa, bb) FORE(bb, aa)
#define debug(x) cerr << #x << " = " << x << endl;
#define debugv(x) cerr << #x << " = " ; FORE(it, (x)) cerr << *it << ", "; cerr << endl;
#define fup(i, a, b) for(int i = (a); i <= (b); ++i)
#define fdo(i, a, b) for(int i = (a); i >= (b); --i)
#define FOR fup
#define FORD fdo
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define ALL(x) (x).begin(), (x).end()
#define CLR(x) memset((x), 0, sizeof(x))
#define MP make_pair
#define PB push_back
#define siz(a) ((int)(a).size())
#define SZ siz
#define inf 1000000000
#define FI first
#define SE second

using namespace std;

typedef long long lli;
typedef double ld;
typedef lli LL;
typedef ld LD;
typedef vector<int> VI;
typedef pair<int, int> PII;

const int MAXN = 100100;
char key[MAXN];
char text[MAXN];

bool solve() {
    scanf("%s", key);
    if (key[0] == '0') return false;
    scanf("%s", text);
    int m = strlen(key);
    int n = strlen(text);
    REP(i, m) key[i] -= 'A';
    REP(i, n) {
        text[i] -= 'A';
    }
    REP(i, n) {
        text[i] = (text[i] + key[i%m]+1) % 26 + 'A';
    }
    printf("%s\n", text);
    return true;
}
int main() {
    while(solve()) ;
    
    return 0;
}