#include <iostream>
#include <string>

using namespace std;

int main()
{
	string a,b;
	for(;;)
	{
		cin>>a;
		if(a[0]=='0') break;
		cin>>b;
		int w=0;
		for(int i=0;i<b.size();++i)
		{
			w=(int)a[i%a.size()]+(int)b[i];
			w=w-64;
			if(w>90) w=w-26;	 
			cout<<(char)w;
		}
		cout<<"\n";
	}
	return 0;
}