#include<iostream>
#include<cstdio>

using namespace std;

int main()
{
	int b,i=-1,k=0;
	 scanf("%d\n",&b);
	char a[100];
	do
	 {
	 	++i;
	 	scanf("%c",&a[i]);
	 }
	 while(a[i]!='\n');
	while(k!=i)
	{
		a[k]+=b;
	 	if(a[k]>'z')
	    a[k]=a[k]-'z'+'a'-1; 	 
		cout<<a[k];
		 ++k;
	}
	return 0;
}