Codeforces Subsequences

题意翻译

求其中**至少**有 $k$ 个**子序列**为 `codeforces` 的字符串 $S$。两个子序列不同当且仅当某个位置的字符在一个序列中出现，而在另一个子序列中未出现。比如 `codeforcesisawesome` 包含四个 `codeforces` 子序列： - **`codeforces`**`isawesome` - **`codeforce`**`si`**`s`**`awesome` - **`codeforce`**`sisawe`**`s`**`ome` - **`codeforc`**`esisaw`**`es`**`ome` 输出**任意一个最短且符合条件**的字符串 $S$ 即可。

题目描述

Karl likes Codeforces and subsequences. He wants to find a string of lowercase English letters that contains at least $ k $ subsequences codeforces. Out of all possible strings, Karl wants to find a shortest one. Formally, a codeforces subsequence of a string $ s $ is a subset of ten characters of $ s $ that read codeforces from left to right. For example, codeforces contains codeforces a single time, while codeforcesisawesome contains codeforces four times: codeforcesisawesome, codeforcesisawesome, codeforcesisawesome, codeforcesisawesome. Help Karl find any shortest string that contains at least $ k $ codeforces subsequences.

输入输出格式

输入格式

The only line contains a single integer $ k $ ( $ 1 \leq k \leq 10^{16}) $ .

输出格式

Print a shortest string of lowercase English letters that contains at least $ k $ codeforces subsequences. If there are several such strings, print any of them.

输入输出样例

输入样例 #1

1

输出样例 #1

codeforces

输入样例 #2

3

输出样例 #2

codeforcesss