#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>

#define rep(i, m, n) for(int i=int(m);i<int(n);i++)
//#define EACH(i, c) for (auto &(i): c)
#define all(c) begin(c),end(c)
//#define EXIST(s, e) ((s).find(e)!=(s).end())
//#define SORT(c) sort(begin(c),end(c))
//#define pb emplace_back
//#define MP make_pair
//#define SZ(a) int((a).size())

//#define LOCAL 0
//#ifdef LOCAL
//#define DEBUG(s) cout << (s) << endl
//#define dump(x)  cerr << #x << " = " << (x) << endl
//#define BR cout << endl;
//#else
//#define DEBUG(s) do{}while(0)
//#define dump(x) do{}while(0)
//#define BR
//#endif


//改造
typedef long long int ll;
using namespace std;
#define INF (1 << 30) - 1
#define INFl (ll)5e15
#define DEBUG 0 //デバッグする時1にしてね
#define dump(x)  cerr << #x << " = " << (x) << endl
#define MOD 1000000007

//ここから編集する
unsigned int rnd(void) {
    static unsigned int y = 2463534242;
    y = y ^ (y << 13);
    y = y ^ (y >> 17);
    return y = y ^ (y << 5);
}

string convert(ll num) {
    string ret = "";
    while (num > 0) {
        ret += char('a' + (num % 26));
        num /= 26;
    }
    return ret;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;
    cout << convert(n) << endl;
    set<string> used;
    rep(i, 0, n) {
        string tmp;
        while (true) {
            tmp = convert(rnd());
            if (used.find(tmp) == used.end()) break;
        }
        used.insert(tmp);
        if (i < n - 1) cout << "a" << tmp << "a" << endl;
        else cout << "a" << tmp << "n" << endl;
    }


    return 0;
}