#include <bits/stdc++.h>

using namespace std;

const string let = "FESTIVAL";

int adds[42];

int main() {
  long long k;
  cin >> k;
  long long x = 0;
  while (true) {
    x++;
    long long smallest = x * (x * (x * (x * (x * (x * (x * (x + 1) + 1) + 1) + 1) + 1) + 1) + 1) + 1;
    if (smallest > k) {
      x--;
      break;
    }
  }
  if (x == 0) {
    string res = let;
    for (int i = 0; i + 1 < k; i++) {
      res += "L";
    }
    cout << res << endl;
    return 0;
  }
  k -= x * (x * (x * (x * (x * (x * (x * (x + 1) + 1) + 1) + 1) + 1) + 1) + 1) + 1;
  for (int i = 7; i >= 0; i--) {
    adds[i] = 1;
    long long step = 1;
    for (int j = 0; j < i; j++) {
      step *= x;
    }
    while (k >= step) {
      k -= step;
      adds[i]++;
    }
  }
  string res = "";
  for (int i = 7; i >= 0; i--) {
    for (int it = 0; it < adds[i]; it++) {
      for (int j = (int) res.length() - 1; j >= (int) res.length() - (7 - i); j--) {
        res[j]--;
      }
      res += 'h';
    }
    for (int j = 0; j < x; j++) {
      res = (char) ('a' + i) + res;
    }
  }
  for (int i = 0; i < (int) res.length(); i++) {
    res[i] = let[res[i] - 'a'];
  }
  cout << res << endl;
  return 0;
}
