#include<bits/stdc++.h>				//Written by ThiDaiLoc
using namespace std;				//Team Three Wolves
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef pair<ll,pll> trp;
typedef vector<ll> vi;
typedef vector<pll> vp;

#define fu(i,a,b)   for(ll i=a;i<=b;i++)
#define f1(i,n)     for(ll i=1;i<=n;i++)
#define fs(i,s)     for(ll i=0;i+1<=s.length();i++)
#define fd(i,b,a)   for(ll i=b;i>=a;i--)
#define fuv(i,a)    for(ll i=0;i<a.size();i++)
#define fdv(i,a)    for(ll i=(ll)a.size()-1;i>=0;i--)
#define ms(a,x)     memset(a, x, sizeof a)
#define prec(n)     fixed<<setprecision(n)
#define uni(a)      (a).erase(unique(all(a)), (a).end())
#define pb(i)       push_back(i)
#define pob         pop_back()
#define sc(a)       cin>>a
#define sc2(a,b)    cin>>a>>b
#define sc3(a,b,c)  cin>>a>>b>>c
#define pr(a)       cout<<a<<endl
#define pr2(a,b)    cout<<a<<" "<<b<<endl
#define rpr(a)      return cout<<a<<endl,0
#define prY         cout<<"YES"<<endl
#define prN         cout<<"NO"<<endl
#define bit(n,i)    (((n)>>(i))&1)
#define lowb(a,n,x) lower_bound(a,a+n,x) -a
#define lowb2(a,x)  lower_bound(all(a),x) -a.begin()
#define all(x)      (x).begin(), (x).end()
#define sz(a)       (ll)a.size()
#define le(s)       (ll)s.length()		
#define re          return 	
#define	mp(a,b)     make_pair(a,b)
#define	mp3(a,b,c)  make_pair(a,make_pair(b,c))
#define se          second
#define fi          first 
#define sse         second.second
#define sfi         second.first
#define soA         sort(A+1,A+1+n)
#define so(A,n)     sort(A+1,A+1+n)
#define sov(v)      sort(all(v))
#define sovr(v)     sort(all(v),greater<ll>())
#define debug(x)    cerr << #x << " = " << x << endl
#define INPUT       freopen("locin.txt", "r", stdin)
#define OUTPUT      freopen("locout.txt", "w", stdout)
inline ll isqrt(ll k) {ll r = sqrt(k) + 1; while (r * r > k) r--; return r;}
inline ll icbrt(ll k) {ll r = cbrt(k) + 1; while (r * r * r > k) r--; return r;}
inline ll mnz(ll& a,ll b){return a=(a>b?b:a);}
inline ll mxz(ll& a,ll b){return a=(a<b?b:a);}
inline string toString(ll n) {stringstream ss; ss << n;return ss.str();}
double const eps = 1e-6;
ll const Base=1e9+7,oo=1e17,MAXN=1e6;


ll A[MAXN+5];
vector<string> F(char c,const vector<string> &vec){
	vector<string>res;
	fuv(i,vec){
		vi v;
		ll p=-1;
		fs(j,vec[i]){
			if(vec[i][j]=='*'){				
				if(p==-1)p=j;
				else v.pb(j);
			}
		}
		if(p==-1)continue;
		
		fu(mask,0,(1LL<<sz(v))-1){
			string s=vec[i];
			s[p]=c;
			fu(b,0,sz(v)-1)if(bit(mask,b))s[v[b]]=c;
			res.pb(s);
		}
	}
	re res;
}
ll Solves(){
	
	ll n,m,k,cnt=0,ans=0,x,y,q,c,sum=0,v,t;
	// PROCESS IN HERE
	
	sc(n);
	vector<string> vec,res; string s=""; f1(i,n)s+="*"; vec.pb(s);
	char cc='a';
	
	while(1){//	debug(cc);
		vec=F(cc,vec);
		fuv(i,vec){
			char dd=cc+1;
			string s2=vec[i];
			fs(j,s2)if(s2[j]=='*')s2[j]=dd++;
			res.pb(s2);
		}
//		debug(sz(vec));
//		fuv(i,vec)debug(vec[i]);
//		exit(1);
		if(sz(vec)==0)break;
		cc++;
	}
//	debug(sz(res));
	sort(all(res)); uni(res);
	fuv(i,res)pr(res[i]);
	
	
	
	
	
	
	re 0;
	// Hack it if you can :)
}

int main(){
	//INPUT;
	if(fopen("locin.txt", "r"))INPUT;
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	ll test=1;
//	sc(test);
	fu(T,1,test){
//		cout<<"Case #"<<T<<": ";
		Solves();
	} 		
}

Measured memory_bytes: 17904