#include<iostream>
using namespace std;

int main(void) {
  int n;cin>>n;
  for(int i=0;i<n-1;++i){
    string s(6,'a');
    int a=i;
    for(int j=0;j<4;++j){
      s[j+1]='a'+(a%26);
      a/=26;
    }
    cout<<s<<endl;
  }
  cout<<"an"<<endl;
}