#include <cstdio>
#include <cstring>

using namespace std;

char key[110],mi[1100];
int n,m;

int ABS(char a,char b)
{
	if(a>=b)
		return (a-b);
	return 25-(b-1-a);
}

char cl(char c)
{
	if(c<='Z')
	{
		return c;
	}else
	{
		return c-'a'+'A';
	}
}

int main()
{
	freopen("vigenere.in","r",stdin);
	freopen("vigenere.out","w",stdout);
	scanf("%s%s",key,mi);
	n=strlen(key);
	m=strlen(mi);
	for(int i=0,j=0;i<m;i++,j++)
	{
		char temp1,temp2;
		if(j==n)
			j=0;
		temp1=cl(mi[i]);
		temp2=cl(key[j]);
		if(mi[i]<='Z')
			printf("%c",'A'+ABS(temp1,temp2));
		else
			printf("%c",'a'+ABS(temp1,temp2));
	}
	return 0;
}