B. Codeforces Subsequences
brute force; constructive algorithms; greedy; math; strings
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.