#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <cstring>
using namespace std;
string a,b;
int _d1(char a,char b)
{
	if(a+b>'Z')
	{
		return char((a+b-'A'+1)%26+'A'-3);
	}
	return char(a+b);
}
int _d2(char a,char b)
{
	if(a+b>'z')
	{
		return char((a+b-'a'+1)%26+'a'-3);
	}
	return char(a+b);
}
int main()
{
	cin>>b>>a;
	int f=-1;
	for(int i=0;i<a.size();i++)
	{
		f++;
		f%=b.size();
		if(a[i]>='a'){
			cout<<char(_d2(a[i],b[f]));
		}
		else cout<<char(_d1(a[i],b[f]));
	}
}