#include<cstdio>
#include<cstring>

using namespace std;

#define max_n 100005
#define FOR(i,a,b) for(int i = (a);i<(b);++i)

char s[max_n];
char k[max_n];
char res[max_n];

int main(){
  while(1){
    scanf("%s",k); if(k[0]=='0') return 0;
    scanf("%s",s);
    int l = strlen(k);
    int n = strlen(s);
    FOR(i,0,n)
      res[i] = ((s[i]-'A')+(k[i%l]-'A')+1)%26+'A';
    res[n]='\0';
    printf("%s\n",res);
  }
}