#include <iostream>
#include <cstdio>
#include <cstring>
#include <string.h>
using namespace std;
char a[100],b[100];
int main()
{
	int n;
	cin>>n;
	cin>>a;
	for(int i=0;i<strlen(a);i++)
	{
		
		b[i]=a[i]+n;
		if(b[i]>'z')
		b[i]-=26;
	}
	cout<<b;
	return 0;
}