Problem:
Score : 1000 points

Problem Statement

#nck {
width: 30px;
height: auto;
}

Welcome to CODE FESTIVAL 2016!
In order to celebrate this contest, find a string s that satisfies the following conditions:

The length of s is between 1 and 5000, inclusive.

s consists of uppercase letters.

s contains exactly K occurrences of the string "FESTIVAL" as a subsequence.
In other words, there are exactly K tuples of integers (i_0, i_1, ..., i_7) such that 0 ≤ i_0 < i_1 < ... < i_7 ≤ |s|-1 and s[i_0]='F', s[i_1]='E', ..., s[i_7]='L'.

It can be proved that under the given constraints, the solution always exists.
In case there are multiple possible solutions, you can output any.

Constraints

1 ≤ K ≤ 10^{18}

Input

The input is given from Standard Input in the following format:

K

Output

Print a string that satisfies the conditions.

Sample Input 1

7

Sample Output 1

FESSSSSSSTIVAL

Sample Input 2

256

Sample Output 2

FFEESSTTIIVVAALL

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>
#include <chrono>
#include <random>

using namespace std;
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define FOR(i, a, b) for (int (i) = (a); (i) < (b); (i)++)
#define RREP(i, a) for(int (i) = (a) - 1; (i) >= 0; (i)--)
#define FORR(i, a, b) for(int (i) = (a) - 1; (i) >= (b); (i)--)
#define DEBUG(C) cerr << #C << " = " << C << endl;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<LL>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using PII = pair<int, int>;
using PDD = pair<double, double>;
using PLL = pair<LL, LL>;
using VPII = vector<PII>;
template<typename T> using VT = vector<T>;
#define ALL(a) begin((a)), end((a))
#define RALL(a) rbegin((a)), rend((a))
#define SORT(a) sort(ALL((a)))
#define RSORT(a) sort(RALL((a)))
#define REVERSE(a) reverse(ALL((a)))
#define MP make_pair
#define FORE(a, b) for (auto &&a : (b))
#define FIND(s, e) ((s).find(e) != (s).end())
#define EB emplace_back

const int INF = 1e9;
const int MOD = INF + 7;
const LL LLINF = 1e18;

string ans[2] = {"FESTIVA", "L"};
int len[2] = {7, 1};

int main(void) {
    LL N; cin >> N;
    LL a[2];
    a[0] = 1, a[1] = N;
    while (true) {
        LL LEN = 0;
        REP(i, 2) LEN += len[i] * a[i];
        if (LEN <= 5000) {
            break;
        }
        int cnt = 2;
        while (true) {
            LL b1 = a[0] * cnt;
            LL b2 = a[1] / cnt;
            if (b1 * b2 == N) {
                a[0] = b1;
                a[1] = b2;
                break;
            }
            cnt++;
        }
    }
    string S = "";
    REP(i, 2) {
        REP(j, a[i]) S += ans[i];
    }
    cout << S << endl;
}