#include<iostream>
using namespace std;
int main()
{
	
	string s;
	string key;
	
	cin>>key>>s;
	
	int i,t;
	
	for(i=1;i<=s.size();i++)
	{
		t=(i%key.size())&31-1;
		if((s[i]&31)-t>0) s[i]=(s[i]&31)-t;
		else	s[i]=(s[i]&31)-t+26;
	}
	
	cout<<s;	
	
	return 0;
}