//P1914 小书童——凯撒密码 正解(teacher's code)
#include<bits/stdc++.h>
using namespace std;
int n;
string s; 
int main()
{
	cin>>n>>s;
	int len=s.length();
	for(int i=0;i<len;i++)
	{
		if(s[i]+n<='z')
		{
			s[i]+=n;
		}
		else
		{
			s[i]+=n%26-26;
		}
	}
	cout<<s<<endl;
	return 0;
}