#include<iostream>
#include<cstring>
using namespace std;
int main()
{char str[60];
int n;
cin>>n>>str;
int b=strlen(str);
for(int i=0;i<b;i++)
{ if(str[i]+n%26<='z'){str[i]+=n%26;
cout<<str[i];}
else {str[i]+=n%26;
str[i]-=26;
cout<<str[i];}}
return 0;
}
