A13495. Codeforces Subsequences

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.

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

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.