CF1368B 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.