#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	string a,b;
	cin>>a;
	int k=a.length();
	for(int i=0;i<=k;i++){
		if(a[i]>=97&&a[i]<=122-n) b[i]=a[i]+n;
		else b[i]=a[i]+n-26;
	}
	for(int i=0;i<=k;i++) cout<<b[i];
	return 0;
}