#include <bits/stdc++.h>
using namespace std;
int main(){	
	int n;
	cin>>n;
	char a[55]={0};
	cin>>a;
	for(int i=0;i<55;i++){
		if(a[i]==0) continue;
		a[i]+=n%26;
		if(a[i]>'z'){
			a[i]=a[i]-'z'+'a'-1;
		}
		cout<<a[i];
	}
	return 0;
}