#include<iostream>
#include<string>
#include<cstring>
#include<cstdio>
using namespace std;
int main(){
	int n;
	cin>>n;
	string a;
	cin>>a;
    for(int i=0;i<a.size();i++){
    	a[i]+=n;
    	if(a[i]>'z'){
    		a[i]=a[i]-26+1;
    	}
    }
    for(int i=0;i<a.size();i++){
    	cout<<a[i];
    }
	
}