#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
char chars[26] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
int main() {
  int n; cin >> n;
  rep(a,26) {
    rep(b,26) {
      rep(c,26) {
	rep(d,26) {
	  if(n>1) {
	    cout << 'a' << chars[a] << chars[b] << chars[c] << chars[d] << 'a' << endl;
	    n--;
	  } else { // n==1
	    cout << 'a' << chars[a] << chars[b] << chars[c] << chars[d] << 'n' << endl;
	    return 0;
	  }
	}
      }
    }
  }
  return 0;
}