#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define Inf 1000000001


int main(){
	
	int n;
	cin>>n;
	string s = "";
	int cur = 1;
	rep(i,10000000){
		if(cur > n)break;
		n -= cur;
		if(i%2==0)s += 'a';
		else{
			s += 'b';
			cur++;
		}
	}
	char c = 'c';
	while(n!=0){
		s += c;
		n--;
		c++;
		if(c>'z')c = 'c';
	}
	cout<<s<<endl;
	//cout<<s.size()<<endl;
		
	
	return 0;
}