#include<iostream>
using namespace std;
int main(){
    int n,idx=0;
    cin >> n;
    for(int i=0;i<n-1;i++){
        cout << 'a';
        int x = idx;
        for(int j=0;j<18;j++){
            char c = 'a' + x%26;
            x/=26;
            cout << c;
        }
        cout << "a\n";
        idx++;
    }
    cout << "an\n";
    return 0;
}