#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <algorithm>

using namespace std;

char key[1024];
char input[100012];

int main(void) {
  for (;;) {
    scanf("%s", key);
    if ( key[0] == '0' ) break;
    scanf("%s", input);

    int n = strlen( key );
    for ( int i = 0; input[i]; ++i )
      input[i] = 'A' + (input[i] - 'A' + key[i % n] - 'A' + 1) % 26;
    puts( input );
  }


  return 0;
}