#include <iostream>
#include <string>
#include <vector>
 
int main(){
  unsigned long long N;
  std::cin >> N;

  auto dict = "abcdefghij";
  
  std::vector<std::string> t[N]();

  t[0].emplace_back("a");
  for(auto i = 0; i < N-1; ++i){
    t[i+1].reserve(t[i].size() * N);
    
    for(auto v : t[i]){
      	for(auto j=0; j <= i+1){
     		t[i+1].push_back(v + dict[j]);
        }
    }
  }
  
  for(auto v : t[N-1]){
   	std::cout << v << std::endl; 
  }
	  
  return 0;
}