#include <iostream>
#include <string>
#include <string.h>

int main()
{
char * input(new char[10005]);


while(true)
{

int cipher; 
std::cin >> cipher;
if (cipher==0)
	break;

memset(input,0,10004);
std::cin.getline(input,10);
std::cin.getline(input,10000);

char * endinput(input);
while (*endinput!=0)
	++endinput;



char * inter(new char[endinput-input]);
char * endinter(inter);
char* pntinter(inter);

for (char * pntinput(input);pntinput!=endinput;++pntinput)
{
	if (*pntinput<='z' && *pntinput>='a')
	{
		*endinter=*pntinput + 'A' - 'a';
		++endinter;
	}
	else if (*pntinput<='Z' && *pntinput>='A')
	{
		*endinter=*pntinput;
		++endinter;
	}
}

char * result (new char[endinter-inter+1]);
char * endresult(result + (endinter - inter));
char * pntresult(result);
*endresult = 0;

for(;pntresult!=endresult;++pntresult)
	*pntresult = 0;

// pntresult wanted at end

for (pntinter = inter;pntinter!=endinter;++pntinter)
{
	pntresult += cipher;
	if (pntresult>=endresult)
	{
		pntresult = result;
		while(*pntresult)  // invariant not full
			++pntresult;
	}
	*pntresult = *pntinter;
}

//for (pntresult = result;pntresult!=endresult;++pntresult)
 //std::cout<<*pntresult;

printf( "%s\n", result); 


delete[] inter;
delete[] result;
}
delete[] input;

return 0;

}