#include<iostream>
#include<cstdio>
#include<string>
using namespace std;
int main(){
	int n;
	scanf("%d",&n);
	getchar();
	string s;
	getline(cin,s);
	for(int i=0;i<s.size();i++)
	{
		if(s[i]+n<='z')
		s[i]=s[i]+n;
		else
		s[i]=s[i]+n-('z'-'a')-1;
	}
	cout<<s;
	return 0;
}