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

using namespace std;

int main()
{

  string key, text;
  
  
  int keyLength = 0;
  int textLength = 0;
  
  getline(cin, key);
  
  
  while(key != "0")
  {
    getline(cin, text);
    keyLength = key.length();
    textLength = text.length();
    
    int tmpkey, tmptxt;
    
    for(int i=0; i<textLength; i++)
    {
      tmptxt = text[i] - 'A';
      tmpkey = key[i%keyLength] - 'A';
      cout << (char) ( ((tmptxt + tmpkey + 1) % 26) + 'A' );
    }
    cout << endl;

    getline(cin, key);
  }
  

  return 0;
}