#include<bits/stdc++.h>
using namespace std;
int main(){
char a[100];
    int n;
    cin>>n;
    cin>>a;
  for(int i=0;i<strlen(a);i++){
      a[i]=a[i]+n;
      if(a[i]>122)
          a[i]=a[i]-26;
      cout<<a[i];
  }
    
return 0;
}