#include <bits/stdc++.h>
#define cs const
#define pb push_back
using namespace std;

int n;

string S[16] = {"aa", "ab", "bb", "bc", "cc", "cd", "dd", "de", "ee", "ef", "ff", "fg", "gg", "gh", "hh", "hi"};
int B = 8; 
vector <string> work(int n) {
    if(n <= B * 2) {
        vector <string> ans; 
        for(int i = 0; i < n; i++) ans.pb(S[i]);
        return ans; 
    } 
    vector <string> c = work(n / B);
    vector <string> ans; 
    int cur = 0, sz = c.size();
    for(int i = 0;i < B; i++){
        if(i & 1 ^ 1) {
            for(int j = 0; j < sz; j++) ans.pb(S[i * 2] + c[j]);
            ans.pb(S[i * 2 + 1] + c[sz - 1]);
        }
        else {
            for(int j = sz - 1; j >= 0; j--) ans.pb(S[i * 2] + c[j]);
            ans.pb(S[i * 2 + 1] + c[0]);
        }
        if(ans.size() > n) break;
    } 
    ans.resize(n);
    return ans; 
}
int main() { 
    #ifdef zqj
    freopen("1.in","r",stdin);
    #endif
    cin >> n; 
    vector <string> ans = work(n);
    assert(ans.size() == n);
    for(string s : ans) cout << s << '\n';
    return 0; 
}