#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,i;
	string ch;
	cin>>n>>ch;
	for(int i=0;i<ch.size();i++)
	{
		ch[i]=ch[i]+n;
		if(ch[i]>122)
			ch[i]=ch[i]%122+96;
	}
	cout<<ch;
}