#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 998244353;
const ll INF = mod * mod;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);

void solve() {
	int n; cin >> n;
	ll c = 1;
	while (true) {
		ll d = (c + 3) / 2;
		if (d*d <= n)c+=2;
		else break;
	}
	string ans; ans.push_back('z');
	rep(i, c / 2) {
		ans.push_back('y'); ans.push_back('z');
	}
	int r = n - (c + 1) / 2 * (c + 1) / 2;
	if (r > 0) {
		c = 1;
		while (true) {
			ll d = (c + 3) / 2;
			if (d * d <= r)c += 2;
			else break;
		}
		ans.push_back('v');
		rep(i, c / 2) {
			ans.push_back('w');
			ans.push_back('v');
		}
		r -= (c+1)/2 * (c+1)/2;
	}
	rep(i, r) {
		ans.push_back('a' + (i % 26));
	}
	cout << ans << "\n";
}


signed main() {
	//ios::sync_with_stdio(false);
	//cin.tie(0);
	//cout << fixed << setprecision(10);
	//init_f();
	//expr();
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}