# include <bits/stdc++.h>
using namespace std;

int n;
string a;
char b[55];  
 
int main()
{
	cin>>n>>a;
	for (int i = 0; i < a.size(); i++)
	{
		b[i] = (a[i] + n - 97) % 26 +'a';  
	}
  	for (int i = 0; i < a.size(); i++) cout<<b[i]; 		 
	return 0;
 }