#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
#include <sstream>
 
#include <algorithm>
#include <cmath>
 
#include <string>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
#include <stack>
#include <list>
 
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////
LL rest = (LL)1e5;
const LL nMax = 316;
LL Nmod = 0;
bool dfs(LL n ){
	if( 0 == n ){
		return true;
	}
	LL sq = (LL)sqrt((LD)n);
	while( (sq+1)*(sq+1) > n ){
		--sq;
	}
	LL next = n-(sq+1)*(sq+1);
	rest -= 2*sq+1;
	if( rest < 0 ){
		return false;
	}
	if( dfs( next ) ){
		char out[2];
		out[0] = char((Nmod)%26 + 'a');
		out[1] = char((Nmod+1)%26 + 'a');
		for(LL i=2*sq+1;i;--i){
			cout << out[i%2];
		}
		Nmod = (Nmod+2)%26;
		return true;
	}
	return false;
}
void solve(){
	LL N;
	cin >> N;
	if( false == dfs(N) ){
		cout << "eieioh";
	}
	cout << '\n';
}

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	
	//cpp
	solve();
	return 0;
}