#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")
using namespace std;
template <class T>
bool umin(T& a, const T& b) {
  return b < a ? a = b, 1 : 0;
}
template <class T>
bool umax(T& a, const T& b) {
  return a < b ? a = b, 1 : 0;
}
template <class T>
void selfmax(T& a, const T& b) {
  a = max(a, b);
}
template <class T>
void selfmin(T& a, const T& b) {
  a = min(a, b);
}
template <typename T>
inline T gcd(T a, T b) {
  while (b != 0) swap(b, a %= b);
  return a;
}
vector<string> split(const string& s, char c) {
  vector<string> v;
  stringstream second(s);
  string x;
  while (getline(second, x, c)) v.push_back(x);
  return move(v);
}
template <typename T, typename... Args>
inline string arrStr(T array, long long n) {
  stringstream s;
  s << "[";
  for (long long i = 0; i < n - 1; i++) s << array[i] << ",";
  s << array[n - 1] << "]";
  return s.str();
}
inline void __evars_begin(long long line) { cerr << "#" << line << ": "; }
template <typename T>
inline void __evars_out_var(vector<T> val) {
  cerr << arrStr(val, val.size());
}
template <typename T>
inline void __evars_out_var(T* val) {
  cerr << arrStr(val, 10);
}
template <typename T>
inline void __evars_out_var(T val) {
  cerr << val;
}
inline void __evars(vector<string>::iterator it) { cerr << endl; }
template <typename T, typename... Args>
inline void __evars(vector<string>::iterator it, T a, Args... args) {
  cerr << it->substr((*it)[0] == ' ', it->length()) << "=";
  __evars_out_var(a);
  cerr << "; ";
  __evars(++it, args...);
}
template <typename... T>
void read(T&... args) {
  ((cin >> args), ...);
}
template <class A>
void read(vector<A>& x) {
  for (auto& a : x) read(a);
}
template <typename... T>
void read(vector<long long>& a) {
  long long n = a.size();
  for (long long i = 0; i < n; i++) cin >> a[i];
}
template <class A>
void print(vector<A>& a) {
  for (auto& x : a) cout << x << " ";
  cout << endl;
}
template <typename T>
T power(T m, long long n, long long mod) {
  T r = 1;
  while (n > 0) {
    if (n & 1) {
      r = (long long)((r % mod) * (m % mod)) % mod;
    }
    m = (long long)(m % mod) * (m % mod) % mod;
    n = n >> 1;
  }
  return r;
}
long long dx[] = {1, 0, -1, 0};
long long dy[] = {0, 1, 0, -1};
const long long MOD = 1e9 + 7;
void solve() {
  long long n;
  read(n);
  string ans;
  set<pair<long long, long long> > sums;
  for (long long i = 1, sum = 0; i <= 320; i++) {
    sum += i;
    sums.insert({sum, i});
  }
  long long cnt = 0;
  vector<long long> pos;
  if (n == 0) {
    cout << 'o' << endl;
    return;
  }
  while (n != 0) {
    auto it = sums.lower_bound({n + 1, 0});
    it--;
    n -= ((*it).first);
    pos.push_back(((*it).second) + 1);
    cnt++;
  }
  char init = 'a';
  for (auto i : pos) {
    while (i--) ans += init;
    init++;
  }
  cout << ans << endl;
}
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  long long t = 1;
  for (long long tt = 0; tt < t; tt++) {
    solve();
  }
}
