#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>
#include<utility>

using namespace std;

#define int long long
#define endl "\n"

constexpr long long INF = (long long)1e18;
constexpr long long MOD = 1'000'000'007; 

struct fast_io {
	fast_io(){
		std::cin.tie(nullptr);
		std::ios::sync_with_stdio(false);
	};
} fio;

int N;

void dfs(string s){
	
	if(s.size() == N){
		cout<<s<<endl;
		return ;
	}
	for(int i = 0; i <= s[(int)s.size()-1] - 'a' + 1; i++){
		char c = i + 'a';
		
		dfs(s + c);
	}
}

signed main(){
	cout<<fixed<<setprecision(10);
	string x;
	
	x = "a";
	
	cin>>N;
	
	dfs(x);
	
	return 0;
}