//p1914凯撒密码
#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;
	int n;
	cin >> n >> s;
	if(n == 0) cout << s;
	else
	for(int i =0; i < s.size();i++){
		if(s[i] >= 'a' && s[i] < 'z')
			 s[i] =  s[i] + n;
		else
			s[i] = s[i] - 26 + n;	
	cout << s[i];
	}
	return 0;
}