#include<string>
using namespace std;
int n = 0;
int main(){
	string str;
	cin>>n;
	cin>>str;
	for(int i =0;i<str.size();i++){
		str[i]+=n;
		while(str[i]>122)
		str[i]-=26;
		
	}
	cout<<str;
	return 0;
}