#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define X first
#define Y second
#define ALL(v) v.begin(), v.end()
#define pb push_back
#define SZ(a) ((int)a.size())

vector<string> gen(vector<string> s) {
    vector<string> vec, res;
    for (char i = 'a'; i <= 'z'; ++i) {
        vec.pb(string(2, i));
        if (i < 'z')
            vec.pb(string(2, i)), vec.back()[1] += 1;
    }
    for (int i = 0; i < SZ(vec); ++i) {
        if (i % 2 == 0) {
            for (auto ss : s)
                res.pb(vec[i] + ss);
        }
        else if (i % 2 == 1) {
            res.pb(vec[i] + s.back());
            reverse(ALL(s));
        }
    }
    return res;
}

bool has_edge(string a, string b) {
    int diff = 0;
    for (int i = 0; i < SZ(a); ++i)
        if (a[i] != b[i])
            ++diff;
    return diff == 1;
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    int n;
    cin >> n;
    vector<string> vec;
    for (char i = 'a'; i <= 'z'; ++i) {
        vec.pb(string(2, i));
        if (i < 'z')
            vec.pb(string(2, i)), vec.back()[1] += 1;
    }
    while (SZ(vec) < n) {
        vec = gen(vec);
    }
    for (int i = 0; i < n; ++i)
        cout << vec[i] << "\n";
    for (int i = 0; i + 1 < n; ++i) {
        assert(has_edge(vec[i], vec[i + 1]));
        for (int j = i + 2; j < n; ++j)
            assert(!has_edge(vec[i], vec[j]));
    }
}