#include <bits/stdc++.h>

using namespace std;

const long long INF = 1e7 + 1;
const long long MOD = 1000000007;
const long double PI = 3.14159265;

#define FOR(i,r,n) for(ll i = (ll)(r); i < (ll)(n); ++i)
#define RFOR(i,n,r) for(ll i = (ll)(n-1); i >= r; --i)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) RFOR(i,n,0)
#define ALL(x) x.begin(),x.end()
#define CALL(x) x.cbegin(),x.cend()
#define RALL(x) x.rbegin(),x.rend()
#define CRALL(x) x.crbegin(),x.crend()

#define cout cout << setprecision(12)

using ll = long long int;
using ull = unsigned long long int;
using ld = long double;
using vi = vector<ll>;
using vvi = vector<vi>;
using vp = vector<pair<ll, ll>>;
using vs = vector<string>;
using vc = vector<char>;
using lst = list<ll>;
using pq = priority_queue<ll>;

template < typename T >
inline void dbg(T a) { cout << a << ' '; }

ll n, m, k, ans = 0, sum = 0, cnt = 0;
string s;
char c;

/*--------------------template--------------------*/

void dfs(string s, char mx) {
	if (s.length() == n) {
    	cout << s << endl;
    } else {
    	for(char i = 'a'; i <= mx; ++i) {
        	dfs(s+i, (i==mx?mx+1:mx));
        }
    }
}

int main() {
    cin >> n;
	dfs();
}
