#include <bits/stdc++.h>
using namespace std;
int dx[] = {0, 0, 1, -1, -1, -1, 1, 1};
int dy[] = {1, -1, 0, 0, -1, 1, 1, -1};
template <class T>
inline T biton(T n, T pos) {
  return n | ((T)1 << pos);
}
template <class T>
inline T bitoff(T n, T pos) {
  return n & ~((T)1 << pos);
}
template <class T>
inline T ison(T n, T pos) {
  return (bool)(n & ((T)1 << pos));
}
template <class T>
inline T gcd(T a, T b) {
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
template <typename T>
string NumberToString(T Number) {
  ostringstream second;
  second << Number;
  return second.str();
}
inline int nxt() {
  int aaa;
  scanf("%d", &aaa);
  return aaa;
}
inline long long int lxt() {
  long long int aaa;
  scanf("%lld", &aaa);
  return aaa;
}
inline double dxt() {
  double aaa;
  scanf("%lf", &aaa);
  return aaa;
}
template <class T>
inline T bigmod(T p, T e, T m) {
  T ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % m;
    p = (p * p) % m;
  }
  return (T)ret;
}
int ar[200010];
vector<int> v;
map<int, int> mp;
int main() {
  int c = 0;
  int i = 1;
  while (1) {
    if (c > 100000) break;
    c += i;
    v.push_back(c);
    mp[c] = i;
    i++;
  }
  int n = nxt();
  if (n == 0) {
    cout << 'a' << endl;
    return 0;
  }
  vector<int> ans;
  while (n) {
    for (int i = v.size() - 1; i >= 0; i--) {
      if (v[i] <= n) {
        ans.push_back(v[i]);
        n -= v[i];
      }
    }
  }
  int t = 0;
  for (int i = 0; i < ans.size(); i++) {
    int x = ans[i];
    int lagbe = mp[x];
    for (int j = 0; j <= lagbe; j++) {
      printf("%c", t + 'a');
    }
    t++;
  }
  printf("\n");
  return 0;
}
