#include <bits/stdc++.h>
#define rep(i,n)for(int i=0;i<(n);i++)
using namespace std;

string Next(string s){
	for(int i=s.size()-1;i>0;i--){
		if(s[i]!='z'){s[i]++;return s;}
	}
	string res;res+=s[0];
	rep(i,s.size())res+='a';
	return res;
}
string s[26];
int main(){
	random_device rnd;
	mt19937 mt(rnd());
	int n;cin>>n;
	rep(i,26)s[i]='a'+i;
	char c='a';
	rep(i,n){
		int d=c-'a';
		cout<<s[d];
		if(i==n-1)c='n';
		else{
			c='a'+mt()%26;
			while(s[c-'a'].size()>=20||c=='n')c='a'+mt()%26;
		}
		cout<<c<<endl;
		s[d]=Next(s[d]);
	}
}