#include <cstdio>
#include <cstdlib>



int main () {

   char txt[100000], key[1000];// vys[100000];
   char c;
   int txtl, keyl, i;
   while(1){
	i = 0;
	txtl = 0;
	keyl = 0;
	while(c=getchar(),c!='\n'){
	    if(c == '0') return 0;
	    key[keyl++] = c;
	}
	while(c=getchar(),c!='\n'){
	    txt[txtl++] = c;
	}
	//printf("keyl = %d, txtl = %d\n",keyl,txtl);
	for(int j=0;j<txtl;j++){
//printf("key[%d] = %c:%d, txt[%d] = %c:%d\n",j%keyl,key[j%keyl],(int)key[j%keyl],j,txt[j],(int)txt[j]);
		//vys[j] = key[j%keyl]+txt[j]+1-'A';
	    printf("%c",(char)((key[j%keyl]+txt[j]+1-2*'A')%26 + 'A'));
	}
//for(int k=0;k<txtl;k++) printf("%c",vys[k]);
printf("\n");
	
   }

   return 0;
}