#include <cstdio>
#include <cmath>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <climits>
#include <vector>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <list>
#include <algorithm>
#include <string>

#define FOR(i,m,n) for (int i = m; i < n; i++)

using namespace std;

char key[1500], text[100100];

int main() {
  while (1) {
    gets(key);
    if (key[0] == '0') break;
    gets(text);
    int lk = strlen(key);
    int lt = strlen(text);
    int k = 0;
    FOR(i,0,lt) {
      printf("%c", ((text[i] - 'A') + (key[k] - 'A' + 1)) % 26 + 'A');
      k = (k + 1) % lk;
    }
    printf("\n");
  }
  return 0;
}