#include<iostream>
#include<string>
using namespace std;
int main()
{string a;
int n;
cin>>n;
cin>>a;
for(int i=0;i<a.length();i++)
{a[i]=a[i]+n%26;
if(a[i]>'z')a[i]=a[i]-26;

}
cout<<a;
return 0;
}