#include <iostream>
#include <string>
#define MAX 110000
#define MAX_K 1100

using namespace std;

int main()
{
    string K,T;
    
    while (true)
    {
        cin>>K;
        if (K=="0") break;
        cin>>T;
        
        int kn=K.size(),tn=T.size();
        for (int i=0; i<tn; ++i)
        {
            char akt=K[i%kn];
            int ile=akt-'A'+1;
            int num=((T[i]-'A')+ile)%26;
            T[i]='A'+num;
        }
        cout<<T<<endl;
    }
    
    return 0;
}