#include<bits/stdc++.h>
using namespace std;

#define rep(i,n) for(ll i=0;i<(n);++i)
using ll = long long;
using pll = pair<ll,ll>;
constexpr ll INF = (1LL<<60);
constexpr ll MOD = (1e9+7);
//constexpr ll MOD = (998244353);
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}return 0;}
#if loc||debg||local||debug
void dump(){cerr<<endl;}
template<class T,class... Ts> void dump(T&& h, Ts&&... t){cerr<<h<<", ";dump(forward<Ts>(t)...);}
#else
template<class T,class... Ts> void dump(T&& h, Ts&&... t){}
#endif
template<class T> istream &operator>>(istream&is,vector<T>&v){for(auto &elemnt:v)is>>elemnt;return is;}
template<class T,class U> istream &operator>>(istream&is,pair<T,U>&p){is>>p.first>>p.second;return is;}
template<class T> ostream &operator<<(ostream& os,vector<T>const& v){for(auto const& vi:v)os<<vi<<" ";return os;}
template<class T>vector<T> vec(size_t a){return vector<T>(a);}
template<class T, class... Ts>auto vec(size_t a, Ts... ts){return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...));}
template<class T>vector<T> _vec(size_t a,T v){return vector<T>(a,v);}
template<class T, class... Ts>auto _vec(size_t a, Ts... ts){return vector<decltype(_vec<T>(ts...))>(a, _vec<T>(ts...));}

int main(){

  int n;
  cin>>n;

  string alp = "abcdefghijk";

  auto dfs = [&](auto&& dfs,string& s,int dep){
    if(s.size()==n){
      cout<<s<<"\n";
      return;
    }
    for(int i=0;i<min(dep+1,n);++i){
      s += alp[i];
      dfs(dfs,s,dep+1);
      s.pop_back();
    }
  };

  string emp = "";
  dfs(dfs,emp,0);

}