#include <algorithm>

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <string>
#include <vector>

using namespace std;

#define FORC(it, V) for(__typeof((V).begin()) it = (V).begin(); it != (V).end(); ++it)

char key[1010];
char text[100100];

int main(void)
{
  for( ;; ) {
    scanf( "%s", key );
    if( key[0] == '0' ) break;
    scanf( "%s", text );
    
    int a = 0;
    for( int i = 0; text[i]; ++i ) {
      int x = text[i] - 'A';
      x += key[a] - 'A' + 1;
      x %= 26;
      putchar( x + 'A' );
      
      ++a;
      if( key[a] == 0 ) a = 0;
    }
    putchar( '\n' );
  }
  return 0;
}