#include<bits/stdc++.h>
using namespace std;
string a,zi("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
int main()
{
	int n;
	cin>>n>>a;
	for(int i=0;i<=a.length()-1;i++)
		cout<<zi[zi.find(a[i])+n];
	return 0;
}